C. P. SNOW'S FIRST NOVEL, written before he was 30, was Death Under Sail, a real detective story with clues and a solution. Now, over a dozen novels later, and well launched into his seventies, Snow has, with that sense of repeated patterns that makes so great a claim upon us as we age, returned to the form of the detective story. One ought to cheer and, according to the prepublication blurbs that fell thick upon me, everybody is cheering. Can I be altogether alone in finding this book a cheat, a crime if you like? It uses all the devices of the detective novel only to abandon the reader in the end to uncertainty and a damp sense of inconclusiveness that resembles nothing as much as bad sex.

Snow's narrative skills are intact. The story line pulls us forward, wanting to know the answer, the reason for all the explanations, all the biographies, wanting, above all, a solution. And that, of course, is what the detective novel of whatever kind must provide. Closure may have vanished from the higher modern literature. The sense of an ending, as Frank Kermode suggests, may be in abeyance. But not in the detective story. We must have an ending, we must know what happened, some sense of order and justice must be restored.

But what if Snow's whole point is that, civilization being but a coat of varnish, order and justice cannot be restored, the answer cannot be found, or if found, proved? This appears to be the case held forth on the book's jacket, which compares Snow to Balzac, Stendhal, Dickens, Dostoevsky and Tolstoy in taking murder as the center of a serious study of life and character. Apart from the fact that even these masters give us sound reasons for knowing "who did it," which Snow does not, it can hardly help this competent, but not great, novelist that to save him from the sin of betraying the detective story, he is compared to the greatest writers of all time.

It is important to emphasize that Snow's problems are not connected with age. Detective story writers particularly -- Michael Gilbert, Andrew Garve, Ngaio Marsh and Rex Stout, to mention only four, all but the last living -- have continued to provide good fare past the alloted biblical span. Many novelists persist in their art into a great age. Snow is guilty, rather, of a particularly youthful sin: presumption. Like a demented spider with a web in which no fly is caught, Snow spins more and more plot lines as though to catch, if not a solution, at least an insight. We have illnesses, bad marriages, hanky-panky in high places, architectural history. All of these aspects of life in Belgravia are supposed, somehow, to have been epitomized by a particularly horrible murder of an old aristocratic woman. But this murder bears (it is my chief complaint about the book) no meaningful connection to the lives of those characters unrelated to her, not even, as it happens, to the man who is supposed to have done it.

One is so annoyed and petulant, of course, because there is much that is good here. Snow has given us a hero past 60, such a nice change, who retires from one job at the beginning of the book to take on another at the end. Having lost one wife by the beginning of the book, he embraces another at the end. This hero has all the charms of a superannuated Lewis Eliot (the protagonist of Snow's Strangers and Brothers series of novels), and his story might well have been told without the murder, and the ponderous insistence upon society's imminent demise.

Perhaps I shall have no deterent effect upon anyone's determination to read A Coat of Varnish. But don't read it for the plot, or else, as Samuel Johnson said in another connection, you may hang yourself. And if you do, please leave a note saying who did it. Murder stories must have an orderly ending. It may be the only order we've got left.