Let’s toss a quick salad of superlatives. Paul Morley’s 1992 interview with non-musician, future theorist and perfume expert Brian Peter George St John de Baptiste de la Salle Eno (conducted for the format-shattering The Thing Is...) is one of the five funniest things seen on television in the last twenty years. (SAE gets you the other four.)

Brian Eno is not known for being funny, which is in itself funny. People see that egg-head, lap-up the professorial air, inhale his Ambient noodlings and assume they have the measure of the man. Sure, he knows a thing or six (even the name’s anagramtic), but forget not that he is also (when he puts a mind to it) one of the world’s most brilliant Pop musicians (the LPs Taking Tiger Mountain (By Strategy) and Here Come The Warm Jets live on a branch very near the top of the Pop Tree). He could have had a nice job in a small town (postmen run in the family) but instead chose to be...Brian Eno.

And what does Brian do all day? We’ve all wondered (oh yes we have), and A Year With Swollen Appendices (one and half inches thick, almost one and a half pounds in weight) tells us everything for 1995. (They call it a diary.) A lot involves marvelling over his young daughters, cooking swordfish with garlic, dissing CD-ROM, lambasting interactivity, and sitting at his computer (Brian doesn’t like computers so much) enlarging women’s bottoms on Paintshop. Brian has a thing about bottoms. And breasts. Exotic porn in general. To Brian, a measure of a country is the measure of its pornography. Ask him and he’ll intellectualise it for you. Maybe he could intellectualise the video cameras in Chuck Berry’s lavatory. Quaint folk, musicians.

1995 was a busy year. He made a collaborative LP with U2 as Passengers (Original Soundtracks 1: it sounds like a Brian Eno LP with unfortunate interruptions); made another with long-time accomplice David Bowie; kicked about the studio with James; presented the Turner Prize (against his wishes); and worked long and hard for War Child.

But reading someone else’s diary is like being cornered at a party by the man who insists, "I had this really weird dream last night..." isn’t it? Most of the time, yes, and no one would, for example, cry out for The Thin White Wallpaper Designer to do something similar. But Brian’s diary is captivating in its balance of the prosaic and the profound. January 6: "Had a bath and then walked for a long time," but only after deliberating on train-spotting: "the desire to be able to understand just a little part of the world, a manifestly controllable part." Or three days later walking out of Pulp Fiction because it’s, "Very slow...and much too archly retro". Besides "Uma Thurman does not give me the horn she seems to give everyone else." (He really enjoyed Die Hard With A Vengeance, incidentally.)

Seldom has a book been quite so endlessly quotable - an aphorism, as someone had it, for every occasion: "Starting to think that all the world’s major problems can be solved with either oyster sauce or backing vocals"; "I guess it’s all right to be wrong if you’re wrong before anyone else"; "Once I found myself saying that, ‘Music is a force for bringing people together’...while in the back of my mind a voice was murmuring, ‘Don’t be such a twat.’" (Why, he wonders, does he have trouble with his erections in Ireland?)

Of course there are problems: in October Brian begins to think of his diary as a possible book - the very one Fabers commissioned years before (for "a £100,000,000 advance") and never received (nice work if you can get it). There is a slight shift when he realises that someone else might actually get to read what he’s writing. It’s only slightly less candid, mind. And, despite mentions over and over, Brian forgets (?) to include the text for his Turner speech anywhere in here. (You might recall that it was by some distance the best thing about the whole sorry exercise.) And Brian’s perception of contemporary art looks to be all over the place; the defence of Jeff Koons, Mark Kostabi, Damien Hirst is spirited, well argued and, frankly Brian, wrong. You can’t win them all.

The last 130 odd pages (printed on pink paper) are the swollen appendices of the title, a gaggle of essays and occasional short stories on this, that and the other: defence; the Lottery; Ambient; Basquiat (proving his artistic mind isn’t entirely skewed); pretension; War Child and the former Yugoslavia (he is both very political and very right); and the music industry. Always smart, occasionally cerebral, often funny, they substantialize (now there’s a word) the trivias of the diary. The book wouldn’t be the book it is (obviously) minus either part.

A trailer: find out how Brian manages to get paid to do an interview with Wired magazine (his reasoning is both arrogant and strangely on the money); how he succeeds in making U2 human and almost likeable (no chance with Bowie, sorry Brian); and what it’s like to be Angus Deyton’s international celebrity stalker.

This is a wonderful book. It takes you from nodding agreement with its erudition on one page to wanting to slap the man silly on the next. But always we’re sure that Brian is as aware of his own pretension as the reader. (And besides, "I decided to turn the word ‘pretentious’ into a compliment.") That’s a very Brian Eno thing to say. Bet you wish you’d thought of it first.