When the Clock Runs Backwards : TIME’S ARROW, <i> By Martin Amis (Crown/Harmony Books: $18; 168 pp.)</i>

The splendid, slender new Martin Amis novel “Time’s Arrow” is bound to become controversial at some point. For starters, it’s about the Holocaust. The central character is a former Nazi doctor from Auschwitz, now known as Tod Friendly (Tod meaning death in German), who is hiding out in the suburbs as the story opens. Or is “opens” quite the right word? The other salient feature of the novel is that its narrative travels backward in time: “One thing led to another--actually it was more like the other way around.” We begin at the tag end of Tod’s existence and finish up with the commencement, as the guy is about to be reborn--or un-born or de-birthed, or whatever you want to call it.

It might be possible to dismiss this bold novel with strategic applications of sarcasm or moral dudgeon--overlooking the small point that Amis’ radical structural ploy is no self-indulgent literary gimmick. The slippery concept may be hard to get a handle on intellectually, but intuitively and emotionally it works like a charm. Ultimately the book’s playfulness, its teasing quality, actually amplifies the emotional impact. It “makes strange” historical events that have been recited often, bringing us right up against them suddenly from new and unexpected angles, and shocking us at the very sight and thought of them, all over again.

Still, there’s no denying that “Time’s Arrow” is a playful book. At first, a fair portion of its entertainment value derives from the zest with which Amis works out the implications of his premise. Because we always get the result first and the cause afterwards, he can toy with us, peppering the narrative with incidental puzzles. A garden patiently tended goes from bad to worse: “All the weeds and nettles (Tod) screwed into the soil--and the earth took this ugliness, snatched at it with a sudden grip. Such, then, are the fruits of Tod’s meticulous vandalism.” And just when we begin to think we’ve really had enough of this sort of horseplay, and are ready to settle down to something a tad more substantial, Amis obliges. In spades.

It’s an intense experience, watching someone get younger rather than older; rather like watching Cliff Robertson get smarter in the film “Charlie.” People not only get younger, they get better, prettier, cleaner, less corrupt; all the marks of their crimes and illnesses fall away. The perversion of ancient medical codes of honor described in the nonfiction classic “The Nazi Doctors,” by Amis’ friend Robert J. Lifton, seem to be confirmed in this topsy-turvy landscape. “Because I am a healer, everything I do heals, somehow,” Tod Friendly insists.

Working as a doctor in the early chapters, Tod seems to make people worse rather than better: They come into his office smiling and feeling fine, and stagger out looking awful. Doctoring hookers, “(Tod) just goes there to rub dirt in their wounds. And backs off quick, before the long suffering pimp shows up, and knocks the girl into shape with his jewelled fists.” As Herr Doctor Odilo Unverdorben of Auschwitz, however, Tod comes on like a miracle healer, and not just of individuals. All that horrendous damage is undone before our eyes, as countless shattered children, families, cultures, entire nations, are magically reconstituted in all their original splendor.

In an interview in the current issue of Details, Amis declares: “What distinguishes the Holocaust from the great brutalities is the state murder of children. So at the end of the book, when he’s a child himself, he suddenly catches on.” Well, yes, but who’s this “he,” exactly? The clock runs in reverse in “Time’s Arrow” only for the narrator, who is explicitly not Tod but a mysterious entity who secretly shares Tod’s existence, “the soul (Tod) should have had, who came at the wrong time, after it was all too late.” Although he seems increasingly to identify with Tod as the book progresses (or regresses), this “entity” is in fact as much a spectator of the narrative as we are, a passive passenger in the skull of Tod, at one point noting that in his roller-coaster new world, not even the escape hatch of suicide is open. And surely, for the premise to work at all, time must appear to be running forward, normally, for the persons directly involved?

Working all the sharp angles in this fiction seems to have restored some of Amis’ relish for the game. A scandalous Young Turk at the outset of his career, Amis in recent years has been morally responsible almost to a fault, embracing social responsibility with all the implacable fervor of a convert. The stories in “Einstein’s Monsters” were glum parables about atomic weaponry. “London Fields” was a science-fiction novel that expanded upon current trends of social collapse. The weight of all that mature concern didn’t exactly put wings to his prose: The high-kicking, scalding flights of rhetoric and invective that graced such wizard early works as “Success” and “Dead Babies” have begun to seem relics of the author’s dissipated youth.

The best news about “Time’s Arrow,” the news with the most profound implications for the future good health of Anglo-American literature, is that it is Martin Amis’ most structurally extreme and thrilling book since his pivotal “Other People: A Mystery Story” in 1981. The book is a sweeping return to form, gripping from start to finish, completely free of the pall of gray London soot that seemed to have settled over the writer’s soul, yet as morally upright as even he could wish. Martin Amis has finally managed to integrate his early literary and his grown-up moral ferocities, to their mutual benefit.