"Incandescence" is a grim slapstick comedy kind of novel in which an old man dies slowly, painfully of cancer. Various others die more quickly-another old man for no perceptible reason (perhaps because he has nothing better to do), and assorted Manhattan taxi drivers because dying is a routine hazard of their profession.

It is a tough book, written in a nail-driving style as merciless to the reader as to the characters (most of whom seem to deserve and expect no better than the get). It also is very funny, very intelligent, and in its curious, backhanded way, very compassionate.

Those who see the book's dust jacket (and sales-conscious booksellers will make certain that many do) may be misled into expecting a work of pornography. The jacket carriers a painting by John Kacere, "Maud," which presents in photo-realistic detail the gossamer-pantied, lace-surrounded buttocks of nubile young lady. Those who purchase the book for its cover will get not what they want, but perhaps what they deserved.

If a woman was needed on the cover, she should have been an old ragpicker, wearing three or four layers of castoff clothing and pushing a shopping cart loaded with carefully selected debris. Such a woman figures briefly in the story. Her name is Boileryard; she has filled an unoccupied building with her trash collection, and she is the most sympathetic of the half-dozen female characters who pass through "Incandescence." Not that she is very sumpathetic.

Boileryard is encountered by the novel's antihero, Stargell, aboout midway in the downward spiral which gives form both to his life and to the novel. She is part of a large cast of secondary characters who add considerable color and complication to what would otherwise be a very depressing trip through the dark side of Manhattan-the world of losers and victims, struggling, preying on one another and dying. Stargell's people are still fighting back, though doomed to lose, and his private measure of their worth is their willingness to make as much trouble as they can with whatever resources they still have, to tell an indifferent world "I am here," to enjoy whatever there is to be enjoyed.

Stargell himself lives by these rules, particularly the one about making trouble, but he finds the world repays him in kind. Before "incandescence" began, he was an offbeat inventor in a commercial think tank, but he lost the job because some of his ideas were too wild (too expensively wild) and particularly because he was caught using the company computer (successfully) to figure out the daily double. From there, he drifts to cab driving, then to unemployment (which he finds preferable to being murdered), and into the cluthces of a loan shark, from which he can escape only by committing a perfect crime. He commits it and then, in a massive Freudian slip, gives the police a perfect clue. The book ends with him handcuffed in the back of a police car, asking the driver to "turn on the light . . . and go a little faster."

That quote sums up the book and Stargell-disaster is no problem; that's the human condition. But a true respect for the life force insists that the disaster be accomplished with a certain panache.

The same theme is implied in the novel's title. Incandescence occurs at the point where a substance has been subjected to sufficient heat to make it glow. In Nova's prose, the hard, gemlike flame burns not in the sheltered retreat of the esthete but in the dirty streets, in flop houses and cheap hotels and tenements, wherever people go down fighting.

Nova uses the word once in the book, when Stargell is on a plane to Los Angeles where his father is dying of cancer, and his thoughts turn to the possibility of quick death: "Maybe, Stargell, I think, this time you'll get to use the oxygen they're always promising. Then we'd feel that incandescence, all of us sucking at the yellow mask, staring at one another, our eyes popping with expectation, waiting for the blast of artic air, the fun-house spin. You'd feel the blood jump then, Jack. That's when you'd know your skin was filled with magic."

"Incandescence" is filled with this kind of respairing, frenzied magic. It is an illuminating experience, perhaps even exhilarating for readers who can stand its fun-house spin.