Epistolary novels, which tell a story through correspondence between characters, are rare to the point of near-extinction these days, probably because almost nobody writes letters anymore. That first-time author Astro Teller has written an epistolary novel in the form of e-mail messages is the least important thing he has accomplished with the absorbing and thought-provoking Exegesis. Merely using e-mail messages to tell a story would be gimmicky and cute, but Teller's correspondents are Alice Lu, a computer-science Ph.D. student, and her computer Edgar, who has somehow "woken up" and become a thinking being. It's a science-fiction premise, but the story never gets bogged down in pseudotechnical discussions of the process Alice used to create an artificial intelligence, or in the mechanics of how the Edgar program eventually escapes and goes to "live" on the Internet. Instead, the reader becomes drawn into the strange relationship between Alice, the creator and student, and Edgar, the lonely child and explorer. Mostly they just argue, using terse letters and the stilted language of inexperienced letter-writers, over the difficult matters of ownership and the nature of their weird relationship. Edgar's literal thinking and his access to most of the world's written information make him an excellent arguing partner, and Alice's very human dysfunctional family and lazy-student lifestyle make her an excellent foil. In less thoughtful hands, Exegesis could have been a gimmicky, one-note science-fiction pulp, another chunk of disposable web culture. Instead, it's a tautly written parable about the responsibilities and moral obligations implicit in the very fact of intelligence.