Terry Gilliam is an elitist. Not through choice but because the populist media has "been taken over by all the wrong people, doing the wrong things and giving out the wrong message." Elitist, but not auteur. He acknowledges in this - a significant addition to Faber's essential Someone On Someone series - that, if any man deserves so labelling, then that man is surely him, but it's a credo with which he doesn't hold. The key to being a good director, he says, "is knowing when to flounce out.".

Two things emerge from this long, copiously illustrated but far from exhaustive (he could talk the hind legs off a donkey) study of Gilliam's eclectic, wayward and frequently brilliant career. Firstly, that reputation scarce does him justice. When the troubled Baron Munchausen went over budget - bad producers, bad faith - Hollywood had him down as a bad boy. And that despite, as he makes clear, audiences actually willingly falling for his extraordinary film. Or that he delivered pictures as rich and rewarding as Time Bandits or his masterpiece Brazil on a relative shoestring. His career since has been about proving them wrong. Which he has, again and again.

The Fisher King was a critical and commercial smash and showcases Robin Williams' best performance, but even after that Gilliam repeatedly failed to get pet projects The Defective Detective and A Tale of Two Cities into production. So he made Twelve Monkeys and gave Bruce Willis his single biggest boost in screen cred, and proved that difficult, dark and challenging could work at the box-office. And still Terry Gilliam is a maverick, a madman. Mind you, his choice to jump aboard a low-budget version of Fear and Loathing in Las Vegas didn't help. Nor his self-confessed impish, even childish imagination.

And secondly? Well, that is that Terry Gilliam is an artist. The book is suffused not only with anger and frustration (and god knows, there's plenty of that), but also a real love, both for the movies and his collaborators. If the vision we see on screen is his (it surely must be, so homogenous a body of work it proves to be), then it is achieved time and again only with the help of others. His descriptions of the ingenious corners cut on Monty Python and The Holy Grail and Jabberwocky will send you back with fresh eyes. He speaks with evident frustration about the former and that other Python film The Life of Brian, about the tensions between co-director Terry Jones and himself: the former intent on action; the latter looking for beauty and historical realism.

Which does rather point up a melancholic aspect to Gilliam. He is clearly frustrated by practicalities, the lack of money and vision in those with the financial veto. There is genuine sadness evident when he speaks about Munchausen, that he knows that, no matter how good it is now, with faith and support it could have been so much better. It is, to him, his great lost masterpiece. And yet it also fits snugly into his own personal vision of Gilliam cinema. "For me, raising questions, instead of giving answers, is what I want to do in films. You don't cross all the 't's and dot all the 'i's."