When the mood came on him, Ernest Hemingway fancied himself in a boxing ring with Tolstoy. For Hemingway, novel-writing was a competitive sport, so naturally he felt obliged to go a few rounds with Count Leo. When Hemingway died, Norman Mailer took over the title of Most Charismatic Novelist, and he too has tried to flatten the competition. It’s a pleasure to see him at 68 weighing in with a novel nearly as long as “War and Peace.” You have to admire the gesture: how many old men have such stamina? Still, there’s something odd here. It’s not Tolstoy that Mailer is challenging: it’s John le Carre–and at the end it’s le Carre who’s left standing.

“Harlot’s Ghost” is Mailer’s big novel about the CIA. Unlike le Carre, Mailer has no hands-on experience with spying, but he tells us he’s been thinking about the CIA for 40 years. That’s what his novel is about: his characters do a lot of thinking about the CIA. And a lot of talking. This is the first spy story in which everyone sits down nearly all the time. They amuse themselves with arguments, lectures, sermons, seminars, cables, reports, a journal and transcripts of taped conversations. Above all, we get letters. Whatever energy the epistolary novel may have had was exhausted two centuries ago, but Mailer doesn’t care. With no coherent plot in view, he’s determined to insulate the reader from what he has to tell us about the bureaucracy of spying by means of a bureaucracy of communication.

This is Harry Hubbard’s story; the time runs from 1955 to 1963. Harry is the perfect scion of the WASP aristocracy-and therefore ripe for recruitment in the CIA. Harry’s father is in the Company’s upper echelons, as is his godfather, Hugh Montague, code name “Harlot.” Loosely modeled on the legendary James Jesus Angleton, who may have gone mad in his country’s service, Hugh is the sort of mentor any apprentice zealot would wish for. Hugh is a theologian manque: he never misses a chance for a sermon. “The rise of Marxism,” Hugh intones, “is but a corollary to the fundamental historical malady of this century: false perception…. Our real duty is to become the mind of America…. The aim is to develop teleological mind. Mind that dwells above facts … Communism is the entropy of Christ. . . "

Heady stuff, but you wouldn’t expect less from Mailer the Manichean, who finds dualities everywhere: God/Devil; Communism/Capitalism; Courage/Fear; in the double agent and the endless duplicities of spying. Hugh’s wife, who becomes Harry’s lover, invents a batty theory involving the duality of the human psyche. Kittredge–that’s this woman’s name, for Mailer knows that the WASP gentry inflict male surnames on their daughters-and Harry set up a clandestine correspondence, as improbable as it is long-winded.

And so we follow bumbling Harry through his CIA training, his first posting in Berlin and his second in Uruguay. The elusive “Harlot” presides over his godson’s progress, keeping him from trouble. In Berlin, Harry becomes involved with the tunnel the CIA has built under East Berlin to tap the phone traffic to Moscow. By the kind of coincidence that can befall a writer who works with real history, this same episode was developed far more effectively only last year by Ian McEwan in his short novel, “The Innocent.” The Uruguayan passage absorbs no more than 300 pages of Mailer’s attention, but its purpose seems to be to introduce E. Howard Hunt, who will be important in the novel’s second half.

The back half of “Harlot’s Ghost” is more interesting than the front. It deals with the CIA’s attempts, under Eisenhower and Kennedy, to get rid of Castro. Most of the characters in the first 700 pages of this book are cartoons: Hugh a demon that Bela Lugosi might have been embarrassed to play; Kittredge less a woman than a metaphysical exhalation. But Mailer can be sharp when dealing with real characters about whom we already know a lot: Jack and Bobby Kennedy, for instance, speak exactly as they did; their attitudes seem true. And with the woman he calls Modene Murphy, who resembles the notorious Judith Exner-bed mate of Frank Sinatra, Jack Kennedy and Mafia don Sam Giancana-he creates perhaps the most entertaining and credible female character in any of his books.

The last line of this immense book reads: “TO BE CONTINUED.” The thought is enough to send a reader in search of a drink. Yet the threat of a sequel does explain why so much plot and portentousness, all pumped like a great balloon at the start of this book, never comes to anything at all. We expect Mailer to offer a comprehensive vision of the CIA’s effect on American society, but except for the excessive Harlot’s gaseous pomposities, he doesn’t deliver. Maybe next time, if there is a next time. Meanwhile we learn again what we’ve always known: too much research is deadly to a novel. Mailer hasn’t written this one from what he knows, but from what he’s learned; it doesn’t spring from his hormones, or his pulse, but from his file cards. And a dry and dusty thing it is for nearly all its incredibly long way.