Until now, Gore Vidal's fiction has mostly been wickedly clever. With his latest novel, Kalki, Vidal ascends into a new category: diabolically clever. I say "diabolically" rather than the more innocuous "devilishly" because what has increased is not the cleverness but the nastiness. Kalki is a hybrid: part social satire; part slick entertainment (in the Graham Greeneian sense); and part doomsday comedy in the manner of, say, Stanley Kubrick's cinematic black comedy, Dr. Strangelove.

Some of Vidal's diabolism manifests itself right away, in the plot's construction. For Kalki is a thriller, and by an ancient and honored custom, reviewers are not allowed to give away the main twist in a thriller's plot. What comes to their aid, however, is that the twist tends to be a single fact near the end of the book, one that the critique can easily sidestep. Here, however, the presumably unbetrayable twist comes...