ON OSWALD'S TRAIL

AT THE AGE OF 72, NORMAN MAILER STILL ROCKS BACK and forth on the balls of his feet when he talks. He still leaves the impression of a compact nuclear device as drawn by Herblock--shaking slightly on its launch pad, Yoda-shaped and oracular, although somewhat mellowed by the years. He is capable now of an occasional shrug that says, "Who knows?"

Mailer admirably settled in years ago for the literary long haul. Whatever momentary noise he made as the Tasmanian devil of American letters (when he would go dervishing through the culture, talking tough, chewing the furniture), his 27 books have drawn a permanent and distinctive trajectory. His obsessions usually lead back into the continuum of the 1950s and '60s, into the universe of the cold war, of media metastasis and dangerous fame, of glamorous, conspiratorial violence, of the garish existential dreads and lusts (to use the old hyperthyroid Mailer vocabulary) that it has been his gift to conjure up.

In Harlot's Ghost, published in 1991, Mailer embarked upon a sort of Moby Dick of the Central Intelligence Agency, with a volume that ran to more than 1,300 pages. A second installment is in progress. Meantime, the industrious Mailer offers Oswald's Tale: An American Mystery (Random House; 828 pages; $30), a kind of nonfiction psychobiography in which he turns his novelist's imagination to the '60s origin myth, John Kennedy's assassination. Oswald's Tale can be judged as investigative journalism or as literature. On either count a fair judgment would be favorable, though mixed. Sunshine and clouds. As in much of Mailer's work, moments of real inspiration and breathtaking shrewdness have been crowded into the same packing case with filler and plodding and, now and then, the sheer bull of a transcendent blowhard.

"The intent of Oswald's Tale," Mailer explains modestly enough, "is not to solve the case--that's beyond my means--but to delineate for the reader what kind of man he was (that is to say, what kind of character Oswald would be in a novel) and thereby enable the reader to start thinking about which plots, conspiracies or lone actions Oswald would have been capable of, as opposed to all the ones he would never fit."

Working with Lawrence Schiller, the investigator and literary operator, Mailer spent six months in Minsk and Moscow interviewing friends and co-workers who knew the American defector in 1959 and the early '60s, when he worked unhappily in a Soviet radio plant and courted and married Marina Prusakova. Mailer and Schiller also interviewed some of the KGB agents who had the stupefying work of following Oswald around, and they read the KGB transcripts from the electronic bugs installed in the Oswalds' Minsk apartment-the intimacies and banalities of quarreling newlyweds. ("Wife: [yells] ... I'm not going to cook. L.H.O.: You could make cutlets, put on water for tea. I mean, I bought everything, everything.")

Mailer's accomplishment--and it is, after all, the purpose he set for himself--is to turn Oswald, that historical smudge, into a troubled, touching human being, rounded and vulnerable and ultimately, Mailer thinks, fatally grandiose: a nut case and nonentity with Hitler-scale dreams. There is perverse American poignancy in the newlyweds' Minsk days, when Lee dreamed of having a son, to be named David, who would grow up to be President of the U.S.