I've just reread this terrific novel. It's set mostly in Greece, and concerns a somewhat oblique character, a risk assessor for an American insurance company, who stumbles upon a murderous cult living in a cave in a remote part of the country. He becomes fascinated by their method of choosing victims, which he comes to believe is based on ancient languages. There is a large cast of characters who eat and drink, discuss the state of the world in restaurants and bars, have affairs with each other, and travel. It's excellent stuff, written in typical deLillo style, oblique, tangential, deliberately vague and obscure.