"I hate that view of the sixties that just invites us all to look in the window at fifty or so people in Chelsea or Soho having a private party, and we weren't invited," says Rob Chapman, author of a major new work on the psychedelic boom of the 1960s, titled simply Psychedelia And Other Colours. "I kind of knew by the early seventies when I first started going up to London at 17 or 18 that what it was they'd all been talking about had already gone. The party had moved on, and all that was left was the dregs of that. It's all very well banging on about love and peace, but what did you change? By 1980 we had Thatcher and Reagan. That aspect has never meant much to me; love and peace is a lovely slogan, but it needs a bit more than that, you know. It always has done."

Alternately damned and celebrated, the 1960s refuse to go away. No other decade, in living memory or otherwise, so blatantly still stands for something in the collective conscience. What exactly that is seems to depend on the perspective and needs of those bringing it up, and whether they intend to use it as a symbolic golden age, a straw man or a shaming stick. Freedom or irresponsibility? Hope and unlimited possibilities, or self-indulgence, hypocrisy and an inflated sense of entitlement? Idealism and generational change, or naivety and blind fanaticism? Two things that people definitely think of when they think of the 1960s however are music and drugs; specifically, guitar-based pop and LSD, and the influence that one had on the other.

It's this relationship that Chapman's weighty tome explores, but it's also about so much more. Psychedelia And Other Colours begins with the origins of LSD before moving onto the drug's early impact on the west coast of America. But this isn't the usual rock-bio rundown of the San Francisco scene, as we're almost 100 pages in before we even catch sight of Jefferson Airplane on the horizon. Instead Chapman focuses on the acid-influenced development of the light show, underground film-making, experimental dance and theatre. The first acid music in this history is made by avant-garde composers like Steve Reich and Morton Subotnick, long before dandified jug bands like the original Charlatans and Warlocks (soon to evolve into the Grateful Dead).

Though he rightly praises Country Joe and the Fish, for Chapman most west coast acid rock is a backwards step from the modernist, multi-media psychedelic experimentation that preceded it. Indeed, he sees surf music as more trippy and space age than most early psych, and in tracing its evolution into what was later labelled garage rock dismisses the notion of the trash aesthetic and points out instead how garage, sixties soul and girl groups like the Shangri-Las were all essentially different angles on the same phenomenon. Hendrix, the Doors and Love all get positive but nuanced appreciations, but it's clear that Chapman's sympathies lie more with the LA pop-psych of the (early) Byrds, the Beach Boys and the Mamas And The Papas than with SF long-hairs like Steppenwolf or Blue Cheer.

The second half of the book focusses on the UK, beginning of course with The Beatles and moving on to Pink Floyd, Soft Machine and how LSD feminised strutting mod pop into something altogether stranger and more ambiguous. Chapman's pocket summaries of bands like the Move and the Moody Blues echo Nik Cohn's brilliant vignettes in his classic of rock criticism, Pop From The Beginning: insightful pen portraits that mythologise but never flatter, maintaining a sharp critical distance without sacrificing a pure, innocent and over-riding love and enthusiasm for pop itself.

Psychedelia And Other Colours also recalls other great music books like Rob Young's Electric Eden or Jon Savage's England's Dreaming, in that it goes far beyond music to discuss social history, architecture, fashion, typographical fonts, television and the wider zeitgeist. It all comes together in the chapter titled 'Penny Arcadia,' as Chapman analyses post-war Britain's melancholy nostalgia for the commonplace and the immediate past, and how this fed into pop art and TV comedy as well as being amplified by LSD use into the main theme of English drug music.

"I've still got an almost utopian, idealistic love of certain pop records from the 1960s, and that remains undiminished by time," Chapman tells me, over tea and cake in his West Yorkshire home, surrounded by Monkees box sets and volumes of twentieth century poetry, the cricket playing out silently on the television before us. "Some of that music still sounds as utterly glorious to me now as it did then, and it's not golden ageing and it's not even being nostalgic, although I do explore nostalgia in the book. I'm asking where does this come from? Where does this feeling of longing and nostalgia and this evocation of the past come from? Why is it in Steptoe And Son? Why is it in The Likely Lads? And a lot of those records even when I was a kid sounded like that to me. You know when you pick up on strains of melancholy when you're younger but you don't know where it's coming from, because you haven't got the emotional repertoire to deal with it at that age? I first heard 'God Only Knows' by the Beach Boys in the summer of 1966, two months shy of my twelfth birthday, and that used to invoke all kinds of strange feelings in me that I didn't know what they were. Why does this record sound so haunting? You're not naturally haunted as an eleven year old; I was certainly a grubby-kneed, falling out of trees, football playing little urchin by then, and yet you hear 'God Only Knows' and it sends you somewhere in your head. What is that longing? What is that? You don't know, because you're 11. And you spend the rest of your life kind of chasing that echo of what that is."

You've spent much of your professional life writing about this kind of music, and I guess a longer time listening to it. With that in mind for such a major work on the whole field- psychedelia and other colours- did you find it difficult deciding where to begin and finding your way in?

Rob Chapman: No. It's a good question and I'll tell you what my way in was. I'd got some ideas for doing a bigger book on the whole picture while I was writing the Syd book [Chapman's 2010 biography of Syd Barrett, A Very Irregular Head], because there's one little section in there when I actually compress the whole of that revived Victoriana argument into a couple of pages. And even when I was writing it I thought, I could have said far more about that. I could only mention it then in association with what Syd was doing, but that's one of my views about how English psychedelia develops: it's part of a much wider periodic revival of Victorian and Edwardian images and ideas. And okay, again, so what? Up to a point all you've got is bands and albums and songs, you know. And then I saw a reference to that book by Nicolete Gray, who I call the Cecil Sharp of typographica in the book, about revived Victorian fonts. And I thought, "Aha, that's my way in." Because they came back in the sixties- well, they periodically revive throughout the 20th century, but suddenly everyone was using that kind of writing again in the sixties. And that was one of those moments when I thought, "Yes, those are my way back." That route led back to Nicolete Gray; other routes led back to Barbara Jones and her book The Unsophisticated Arts, another one of the Holy Grails in that book. So that's what got me started.

Also, your question was you've written about it professionally and you've spent a lifetime listening to it; I have to say that the lifetime listening to it is actually far more important than the professional life writing about it. I drifted into music journalism when I was forty. I don't have a typical career path in music journalism at all. I drifted into it, enjoyed doing it for five or six years and then I kind of stopped enjoying it and eventually drifted out again. I'm now pretty much redundant as a music journalist. It's definitely the years of listening to it beforehand that's more important.

Yeah, and I guess thinking about it, if not writing about it for somebody else.

RC: I muse on this stuff all the time. I'm away in my head a lot of the time; my wife calls it pop clouding. One day she was annoyed about something and she said, "Oh, come off your pop cloud!" And pop clouding means I could be in there washing up or anything, but what I'm really thinking about is some obscure 1968 Deram single. And that bit's more important. It's like that criticism of Picasso: a child could do that in five minutes. And Picasso said well it took me ninety years and five minutes, meaning it's the bit leading up to it that's important. And in the same way that book took me fifty years and three years to write. I was 12 years old in 1966, and that's quite important to me; your formative years. I'm of the age where I heard 'Penny Lane' and 'Strawberry Fields' at 12 years old, and that means you're old enough to be thinking this is wonderful, this is marvellous. There's a trace element of that I've chased for the rest of my life.

I approached your section on the Beatles thinking what else can anybody possibly say about that band? And you seem to have dealt with that by taking a very subjective point of view. You've written about your experience of hearing them as a child and how it seemed to you then.

RC: And also reinventing them as a girl group; I think that's pretty radical! But yes, I decided to be utterly subjective about it. And you're quite right, yes; what on earth is there left to say about the Beatles after all this time? And my view was one of belligerence, actually: well, anything I goddamn want. And why? Because I was eight years old when 'Love Me Do' came out, and that was my starting point. I wanted to write about them from the viewpoint of someone who grew up with that music, who hasn't just tuned into the myths. If we're going to mythologise then let's have some fun with it. My view, which I didn't fully articulate in the book, was that the Beatles go through five stages. They start off as a boy band in Germany; then they become a girl group; then they become, during their pot smoking period, a male pop group again, and a great soul group as well actually, and a chamber pop group; then with LSD they become feminised again, and then they end up in the late sixties as a male rock band. So it goes male-female-male-female-male; five stages. I didn't elaborate that fully in the book, and that still would be aiming for some ridicule now. But when you look at the early stuff you just think yeah, they're a girl group by surrogacy. And so are lots of those groups.

It doesn't seem particularly contentious once it's said.

RC: The other area in which I really wanted to mention the importance of the girl groups was they are the great missing link in the period of surfadelica and garage bands as well. They play off each other: the crucial difference is the girls have their chorus, and the boys just howl alone through a barrage of fuzz. I thought, all that male angst is just coming from being rejected by girls, and the girl groups are singing just the same songs about being rejected by boys, and there's this great dance between the two going on. I hate the way the girl groups get written out of pop music history. I've no time at all for anyone who says oh, after Elvis goes into the army nothing else happens until the Beatles, which is why I wanted to have that rundown of the chart in the week that the Beatles first broke in America. The week that 'Can't Buy Me Love' gets to number one, when you look at what else is in that top 30 it's a fantastic top 30, and they replaced 'Louie Louie' at number one! I've never seen that mentioned anywhere at all! What was this barren scene that they replaced? It was the record that went on to be the template for garage rock and probably punk as well.

You seem particularly sympathetic towards the manifestations of psychedelic culture in popular children's TV shows and light entertainment. I'm a bit younger than you, but certainly growing up as a kid in the seventies and eighties my first exposure to psychedelic music would be watching reruns in the school holidays of the Monkees or Batman or the Banana Splits, and hearing old Beatles or Moody Blues song on Radio 2. You didn't have any exposure to the 13th Floor Elevators or the Stooges or any of these now-hip bands that everyone can now listen to; you came in via that almost kitsch, middle of the road angle. And that leaves a residual fondness for that stuff as much as for supposedly more authentic psychedelic rock. Do you have childhood memories of these TV shows that influenced you?

RC: The first thing I would say is that I have no idea what authentic psych music is, and I have no wish to pursue that either. To me the idea of real psych is a paradox. I can't see how you can have such a thing as real psychedelia when the whole thing is based on a psychedelic drug that gives you hallucinations and illusions and layers and layers of unreality.

You explain that very well when you talk about the main acid revelation being the idea that we're all wearing masks and playing games anyway, so what is false and what is real?

RC: That occurred to me during the writing of the book. You might think that that's something I'd thought about for years, but that is one of the key things that occurred to me during the writing of the book, that masque play; but that's another question entirely. Let's come back to that in a minute. Let's go with the childhood stuff: most definitely, and I'm not sure how kitsch it was either. My editor said to me very early on, where are you going to end this book? And I think he meant where chronologically, and I was determined that I wasn't going to try to bring it up to date. People have done that in books, and I find they get a bit boring, because once you get past the late sixties, early seventies it becomes just a question of writing about psychedelic revivals, and I didn't want to go that route. I thought the route I want to go down is to approach it from the point where it all becomes assimilated into the mainstream.

To me the idea of just writing about it as this precious little underground thing is not of interest. What interests me, and I suppose this is the answer to your question, is that stuff appeared on TV very quickly. And late sixties children's TV was really trippy. For a start, yes, you've got the Monkees, but if you think in the space of a couple of years, when I was 14 or 15, you had Do Not Adjust Your Set, which was the Bonzo Dogs and the future Monty Python people, that used to go out on a Tuesday evening at 5.20. You had Nice Time with Kenny Everett, Germaine Greer and various other people, which used to go out at half five on a Sunday night, that was quite psychedelic, and all of those programmes were going out at children's TV times, with trippy graphics and trippy ideas. I suspect it was because people of that generation were coming through and getting into TV; there was that first intake of people into the media who were of that mind set. Vision On was like that too. Later on I think it got a bit folksier and a bit more standard children's programming, but quite early on they used to have very trippy stuff they would make on there. I mentioned this at one of the festivals I did recently: when they used to do the gallery they would pan along the paintings on the wall and they would have some standard generic music for that later on, but I remember them using music like Frank Zappa's 'It Must Be A Camel' from Hot Rats and things like that. This would have been slightly later - 1970, 71. And that became quite common: you would get trippy music in these programmes. So it's assimilated through children's TV.

Getting back to the idea of the supposedly kitsch vs the supposedly authentic; given the acid revelation that it's all a play anyway, the notion of making a cult of authenticity within psychedelia seems quite ludicrous. Equally ludicrous is the idea of rejecting commercialism in pop music, which is intrinsically a commercial form, and obviously the more psychedelic it gets the more it's about pretending, which is why it's perfectly valid for you to give equal weight to brilliant psychedelic pop bands like the Moody Blues and the early Bee Gees and particularly the early Status Quo, which okay is somewhat ersatz but it's great.

RC: Do you think so? Because I love that stuff, and I suspect I'll get a bit of criticism for that. I suspect there'll still be a few people who'll be a bit sniffy about all that, saying oh, he bangs on about the Bee Gees or Status Quo.

I've long been a fan of all that stuff; partly because it wasn't cool or obscure and so you could always find it cheaply in charity shops.

RC: That's part of my criteria for record buying, certainly. What was it first attracted you to this album? Well, the 50p sticker primarily. Yeah, I've got a whole bunch of that stuff.

But it does sort of tie in with this idea of being exposed to this music through shows like the Monkees: there's a love for this bright, plastic, slightly fake take on psych that's great not in spite of being a bit ridiculous but actually partly because of it.

RC: Part of what I wanted to talk about was why are groups like the Moody Blues so critically derided? Because when you listen to their lyrics they are quite heartfelt songs about finding your way in this world, and finding an answer. And I'm thinking well, why is that any more kitsch than some singer songwriter like James Taylor or Joni Mitchell? And I came to the conclusion that a lot of critics who deride that probably deride the kind of people who like that anyway. They probably look down on straight people and their straight ideas of how to get through this life. And straight people bought that music in their thousands. Not everyone who buys this music took drugs, you know.

There's nothing the slightest bit tongue in cheek about the Moody Blues.

RC: No, there's not, is there?

I think they're completely genuine and they seem like really straight guys who have taken acid and then are like, what is this all about? And want to actually properly explore this.

RC: This is the thing; they look really straight.

Like the Beach Boys, as well.

RC: Yes, and the Association, and I think every Association top ten single was about drugs. I've forgotten his name, that genial Hawaiian guy who replaced the original one who went off to India, when you see him standing there singing "I took off my watch," beaming away, "I thought I had all the time in the world." It's like yes, we know why! That metaphorical watch! But again it's the same when you look at the surrealists and the Dadaists in photos in the twenties and thirties; they all look as straight as anything. Apart from Dali, who's looking self-consciously whacky, the rest of them look like bank managers and solicitors. And you think this is Max Ernst and Tristan Tzara we're talking about; these people did the strangest, most mind-blowing fucking art of the twentieth century, and they all look as straight as dies.

You celebrate another favourite of mine right at the end of the book, the Four Seasons' Imitation Life Gazette. The Four Seasons are a brilliant pop band anyway, but that album is a fascinating record, and again they do seem really genuine; they're not bandwagon jumping, they're these quite straight artists who very seriously and genuinely seem to want to explore what is all this about, and are taking the opportunity to go a bit deeper and be a bit introspective.

RC: Mark E Smith said the weirdest guys I've ever known in my life have been the straightest looking guys, and I've often thought that. Some of the weirdest people I've ever known have been really straight to look at. Whereas someone with blue hair sometimes you meet them and you think all of the input really has gone into the hair, hasn't it?

Similarly it can be stranger and more effective when rather than some long-haired band going crazy with a fuzz pedal or whatever, you've got almost easy listening pop but weird, trying to be psychedelic but not quite getting it right, and that is more unsettling and more effective in a way than just making some kind of fuzz-phased monster.

RC: Yeah, it can be. I was never a fan of a lot of the west coast groups. I had to write about them, but when you listen to a lot of that music, especially for young people, if you present something like Quicksilver Messenger Service to them now, they're just going to hear some stodgy old blues jam and they're going to think where's the psychedelia in this? I think the perfect mechanism for realising psychedelic music is the single, the two and a half, three and a half minute single. I don't think it needs ten minute extemporisations on Bo Diddley. In fact that gives you plenty of time to get bored, and particularly the kind of blues-rooted jams that those groups were pursuing. In that respect the krautrock groups are far more psychedelic. Faust are a far more psychedelic group than Quicksilver Messenger Service. But I couldn't write about that and I had to champ at the bit in a way when I got to all that stuff, because a lot of those groups were as trippy as the sixties groups were, but that would have meant going on through all the rest of it.

So it's not so much challenging orthodoxies for the sake of it as wanting to have your say and give your version of the music that you lived with. This seems entirely natural; that if you're writing these books, you're going to want to have your voice. It's surprising how few writers actually want to have their own take and how many are happy to regurgitate, just to show that they've read the accepted books and that they can regurgitate the accepted version.

RC: You say about not hearing their voice in there: my mate Gavin says quite simply that's because most of them have got nothing to say. That's his view: they're catalogue freaks. They like listing things, they like knowing what order everything went in, but it's like the price of everything and the value of nothing. That's his view, not mine, but it is that: sometimes people don't put anything of themselves into their work because they haven't invested anything in there, you know.

You quite wisely avoid at any point trying to define psychedelic music.

RC: Thank you, I'm glad you noticed. No, I don't, and that is quite deliberate.

You talk about 'psychedelic' historically in the sense of what Osmond and Huxley meant by the term, but you don't say what is psychedelic music.

RC: Yes, because I don't think I have a right to. I don't want to condemn myself by telling too many stories that begin "I was tripping, right," but I was tripping right, and we were in London, and we were near Regent Street and they'd just turned on the Christmas lights. We were going to go and look at them but we got to this place in the road where - it wasn't an underground toilet but there was this kind of glass casing underneath a grill in the road. And there was obviously some kind of basement or workshop down there or something, and there was this faint light coming through it. And my mate, because we're tripping he goes hey look, these are the lights, you know. So we went with that for half an hour: these are the Christmas lights, nobody knows but us. And if you can find heaven in a grain of sand when you're tripping, or if you can find the Christmas lights in a little two foot by three foot underground shaft and you can go with that for half an hour - that's why I utterly refuse to define psychedelia. Some poor people will use that as a point to give me two star Amazon reviews with: "I read this entire book and not once does he define psychedelia." No, and I had no intention to, either.

I don't think you're condemning yourself, given that you've written a book about the effects of LSD, by saying you've actually taken it. It's probably good that you know whereof you speak.

RC: Yeah but at the same time I don't want it to be a book for drug bores. And also I didn't want to just tell lots of drug stories. What would happen then is you make a rod for your own back, because all the reviews will begin "self-confessed acidhead Chapman, 60, says…" And I didn't want that. That is the bit I didn't want to be all about me, me, me. Yes my voice is in there throughout the entire book, implicitly as much as it is explicitly, but I didn't want to take away from this great body of knowledge and human creativity that the drug has given us.

It seems to me that while you don't suggest that LSD gives anybody the key to the universe or the meaning of life, you do imply that it makes for quite a nice holiday.

RC: Yes, because in the end that is my philosophy. I worked out in the end that it's a lovely away day, but you wouldn't want to hammer a philosophy to its kite tails.

It's a nice place to visit but you wouldn't want to live there.

RC: No, because you couldn't! I'm being serious about that because somebody did ask me that question at one of the talks. Right at the very end he asked about the changing world consciousness. I thought fucking hell, right at the end, you know. I had to say to him, "I'm not going to be able to do your question justice"; it was the very last question. But I said in terms of philosophy what you've got to come up with is an aesthetics for ephemera. You've got to come up with an aesthetic that can deal with the fact that this feeling is only transient. And I know you think I probably wrote slightly too much about the light shows, but it was important to trace that because in some ways is the perfect acid medium. It's not just a static image on a wall; it's permanently changing. Now in the end light shows did turn into what I call a fractal orthodoxy; you did get used to seeing the same old blobs and images. But that to me was the perfect medium, ever changing and ever transient. So for me it did involve, rather than trying to come up with one of these bogus lifestyles, like Timothy Leary, who I think was a very dangerous man - not to mention a CIA informer - it was to sort of dismiss that aspect of the drug culture and say, "Right, well what do you do with this ephemera? What do you do with the fact that it is transient, and it does just give you a glimpse of heaven?" Well, so do three minute pop records. And that's why I think the three minute single is actually a perfect medium for it. You can encapsulate it all into that one little song. The groups who could do that did it wonderfully I think. I won't name examples because you know who they all are: you can choose any one of a hundred great psychedelic pop singles. So let's actually deal with the aesthetics of ephemera; let's deal with the politics of transience and impermanence and see where that takes us.

Psychedelia And Other Colours is out now, published by Faber