In the Wake of Dr. Strother : DOCTOR SLEEP, <i> By Madison Smartt Bell (Harcourt Brace Jovanovich: $19.95; 304 pp.)</i>

To say that an air of unreality hangs over a book is not usually a compliment. To say it about “Doctor Sleep,” the new novel by Madison Smartt Bell, is to describe one of its greatest strengths.

Let’s start with the title. Adrian Strother is not a doctor--although people persist in addressing him as one--but a hypnotherapist; as for the sleep, he spends most of the long weekend of the book trying to break a bout of insomnia which has for several days been driving him to the edge of sanity. He is a displaced person anyway, a hip young New Yorker who left America to escape a drug addiction, now lives in London’s seedy Notting Hill, and during the book travels all over London from the British Museum reading room to a pub in Chelsea to Harrods tea room to Wapping docks to, well, you name the part of London, he goes there.

When he does go out, he is followed--or is he?--by two hoods, one of whom sports a Statue of Liberty haircut; when he stays near his home, he is blasted by the famously jubilant--and potentially violent--Notting Hill carnival, which is going on. His girlfriend has left him; his pet snake refuses to eat the live mouse he has given it for dinner. He has conversations with people who are not there, and occasionally cures wounds by self-hypnosis. Often, he stops to ponder on his real specialty, the Hermetic myth and the writings of 16th-Century philosopher Giordano Bruno. It’s none of it quite like real life.

It is, on the other hand, an extremely vivid account of the way real life seems when you can’t quite handle it. Adrian Strother simply never has the time to catch up with himself. During three days, he finds himself chasing his girlfriend, being chased by a drug trafficker, dealing with a former junkie friend from New York now turned anti-drug evangelist, resurrecting an old love affair, taking on a new client with multiple personalities, performing a magic show, half-killing himself practicing an Oriental kind of self-defense . . . the list goes on and on. Always, he is remembering he is late for an appointment; always he is sidetracked somehow into another. Throughout the book, his eyes itch; he tries to eat and cannot; he drinks and regrets it; he longs for and dreads the night. As a portrait of a man on the brink, it is remarkable.

The book has not one story line but several, and--inevitably with so much crammed into 304 pages--some are more successful than others. A subplot involving a brutal series of murders is brought to a too-pat ending, but adds a nice frisson of suspense on the way there. The Hermetic myth is invoked constantly and with an air of great significance, but since the myth never is explained precisely, it is difficult to see quite what point is being made by it. On the other hand, Strothers’ confusion about why his girlfriend has left him is both realistic and moving; and a story about a woman with multiple personalities packs a real wallop.

If all this is beginning to sound either confusing or depressing, it is neither: It’s a rip-roaring good read.

Even the book’s great failing, its portrait of the English, ends up by adding to the atmosphere. Bell is an American who clearly has lived in, and loves, London: His portrayal of the city itself--accurate down to the names of the most obscure alleys, the nightmarish rock and bump of the tube trains, the flowers in the churchyard by Putney Bridge--is such as can only be born of deep affection. But its inhabitants, the Londoners, are no more than cartoons. They are called names which no one has been called for years, like Sid, or Nell, and their dialogue--lots of “orright, Guv” and “you shut your bloody hole”--is straight out of the worst of bad movies. In other books, this would seriously impede the enjoyment; in the strange dreamlike world of Adrian Strother, it actually becomes part of it.

Apart from this, the language of the book is a joy. Listen to this for a miserable morning: “It was gray, grim gray, in the cold bedroom, and the air had the feel of wet cement.” Or this for a crowd scene: “I felt like a particle of a lot of toothpaste being slowly rolled toward the top of the tube.” Or this for two karate partners: “Trust someone to almost kill you barehanded, but not quite; trust yourself to do the same for him . . . There’s nothing that feels quite like that, though perhaps a couple of things come close.”

All in all, “Doctor Sleep” is an extraordinary book, haunting, overwhelming, sometimes confusing, altogether unforgettable. You may find some of its passages too long; you might be irritated by the frequent, not always explained, jumps from reality to fantasy and back again. But there is a pretty good guarantee, when you have read it, that the next time you have insomnia, or jet lag, or a hangover, or are simply feeling too stressed to cope, you will find yourself thinking of Adrian Strother.