In a hip hop arena that often rewards the championing of ego over talent, Mos Def remains an enigma. Now 35, and four intriguing albums deep, he has managed to balance high-level cinematic excursions with a burning desire to remain a multi-genre artist. Large sales — P Diddy if not Jay Z — would be an easier option, for no classic single has emerged from any of these albums. Instead, and, I suggest, uniquely, the music spreads to gargantuan proportions, an arena in itself where hip hop conservatism is allowed to play no part.

The Ecstatic is, therefore, a continuum. The artistry remains understated, modest even; and, yet again, it takes several plays before the gems begin to form. Herein you will find a spinning multi-coloured paint box where the punch of hip hop is tempered by unlikely shards of jazz and jazz-funk, soul, electronica and (I can't think of a better name for it) voice-doodling. Taken as a whole, it's a wild and vivid dream, locked into the contemporary by Mos Def's omnipresent polemic. The Ecstatic begins with a clip of Malcolm X talking about meeting extremism with extreme methods and how he will join with anybody to make an extreme change. You listen to this and wonder how it sits with Obama conservatism, let alone that of hip hop's glittery illuminati. This is thrilling and almost dangerous.

And yet, although this is a profoundly politically aware album even that is not at the expense of sexuality. So is it too much? Does it spread so thinly that first-time listeners might feel rather distanced? It is, after all, impossible to place on the radar and, in the world of solid categorisation in which modern music rather deadeningly exists, this is a rare thing indeed.

The lyrical themes of The Ecstatic are equally disparate; 'Life In Marvellous Times' is a case in point. The spirit of a twelve-year-old Mos Def is hereby evoked, living in a dream through the raging heat of a Bronx summer. This was where his personal discovery of hip hop began — right at hip hop's source, when the groundbreaking artists were genuine local heroes and the bright young Mos Def could only wander about, soaking in the immense energy. Even then, he knew that something extraordinary was happening in his neighbourhood. After seeing Wild Style in his local cinema, he became instantly determined to remain true to his aesthetic course. He was on his way.

Much of The Ecstatic does seem to have evolved from this boyhood. It's almost as if his own personal musical trajectory instantly veered from a hip hop top-heavy with crassness, vulgarity, sexism and the celebration of male ego. (I generalise; swathes of inspired sounds have also emerged.) Mos Def however, appears to have remained aloof — an existentialist in a world that clubs together in knots and gangs.

As such and in spirit, this probably sits closer to Miles Davis than Eminem. Mos Def took three steps back and took on board a holistic view that encompassed punk bands, jazzers, soulsters and rappers. Not for him, however, the crass crossovers of Run DMC: nowhere on The Ecstatic does the music seem so laboured. It's allowed to flow free, for better or worse.

Mostly, it works. Whereas previous albums — Black on Both Sides ( a playful musing on hip hop's world status, delivered from his Brooklyn hangout) and the Manifest Destiny album (which saw him in league with his brother, D.c.Q and female friend rapper MC Ces) — have pushed at the boundaries, The Ecstatic appears to have escaped, and now he runs amok. That' the key here. While every track contains autobiographical elements, this truly is the joyful sound of a rampant artist, unrestrained by expectation or commercialism.

Well, that's merely stroking the tip of the iceberg, to be honest. The novelistic quality here begs numerous listens, and I'm only six plays in. I guess this is as close as anything gets to the fantasy path that a pure hip hop might have taken from that 1982 base. As such, The Ecstatic will not trouble the mainstream; indeed, it seems certain to keep Mos Def locked in glorious aloofness. Well, he is lucky. His alternative career should keep his star afloat. I just hope he goes on; I hope he remains hip hop's great existentialist.