This book is not for experts in computers or artificial intelligence. My audience is ordinary people who are curious enough to ask questions like these, and who want to be able to make informed decisions about the course of AI's development. It is even for those who think that all this is rubbish--that no matter how smart machines get, they will never truly think, have a soul, or be self-aware in the same sense we are. Whatever your leanings, it should do no harm to explore, poke around, ask questions, and try to find out what makes machines so smart, what their inherent limitations might be, and where the boundary between human and artificial intelligence might lie. If these questions make you vaguely uncomfortable, it may be because they challenge the very foundations of all our social, legal, and religious institutions. Because there are already lots of books about the mechanics of AI, as well as works of fiction and nonfiction that speculate about future worlds inhabited by thinking machines, it is reasonable to ask what new territory I hope to cover here. We will explore an unfamiliar land along the boundary between science and human values. There, we will seek out the logical structure of human feelings, consciousness, and morality that would make it possible for machines to possess them as well. Then we will delve into the social, moral, ethical, and religious consequences of creating thinking and feeling artifacts.