At the center of the book are Ralph Messenger, director of a prestigious center for cognitive science and an expert on artificial intelligence and human consciousness, and Helen Reed, a recently widowed novelist, just past 40, who turns up at Gloucester to teach a fiction-writing workshop. Ralph is married to Carrie, a wealthy American, but is known as a womanizer. Helen is still grieving for her husband, who died suddenly of an aneurysm. On the one hand, Helen is just another new, attractive female who appears on Ralph's radar screen and so his interest in her is unremarkable. On the other hand, Helen and Ralph have a lot in common: As a novelist, she's just as interested in the mysteries of human consciousness as he is, and the wildly different approaches of their chosen fields to this central enigma of existence are fodder for fascinating conversation.

Lodge sets up the novel in a way that's ingeniously suited to his subject: Ralph is conducting an experiment to try to determine the nature of thought, so he talks into a tape recorder freely and later transcribes the stream-of-consciousness ramblings; Helen, for her part, is an inveterate daily journal writer. So we get to observe their meeting and the progress of their acquaintance from each participant's private point of view, as well as occasionally see them in chapters written from an objective third-person perspective. Hearing Ralph's freely flowing thoughts, in particular, is hilarious, as he wanders in a perfectly believable way from sex to food to work to sex to an incident from the evening before to sex, and so on. Helen's diary reveals her as a more reserved, ruminating character, less compelling (and at times less believable) than Ralph. But she becomes more interesting as the plot confronts her with opportunities to rethink things she thought she knew about herself and, at last, to come out of her paralyzing grief over her husband's death.

Watching Ralph try to seduce Helen right under the nose of his wife is fun -- somehow Lodge makes it seem not sleazy. There's a generosity to Ralph's sexuality, even in potentially eye-rolling situations, such as when he beds a graduate student at a conference in Prague. Everyone in "Thinks" is constantly striking his or her own moral bargains; in that episode, the much-younger woman who pursues a powerful older man is conniving for her own interest and gets just what she wants out of the deal. As for Carrie, Ralph's wife, Lodge manages to make her an interesting character in her own right, much more than a passive victim of her philandering husband's shenanigans. It helps, of course, that she holds the family purse strings and that Ralph couldn't leave without a big drop in his standard of living, but if Lodge has to at times strain credulity to keep his playing field level, so be it.

In "Thinks," as in his other books, Lodge's academics hold our attention not just because he gives them complicated sex lives and good senses of humor but also because he shows how seriously they take their work. "Thinks" provides us not only with an engaging, accessible overview of scientific debates on human consciousness but also with a look at the ways in which the humanities and the sciences are trying to find a common language to talk about matters that concern both. Forget clichéd notions about the boredom of academic life -- while Lodge pokes fun at the pretension, the slowness, the provincial attitudes and the stultifying bureaucracy of the university, he makes his characters' actual work seem fascinating. The chance to have a life of the mind, after all, is one of the few benefits academics get (though many seem to squander it). In the end, we feel lucky to have spent some time thinking over the problems of consciousness and, of course, of how to go about life in general, in the company of characters as genuinely likable as Ralph and Helen.

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Maya Angelou reads from "The Heart of a Woman"