The "river" to which Dawkins refers in the title of this little (172 page) book is the river of digital genetic information that connects us to our human ancestors and to the rest of life on our planet. I find this metaphor to be an extremely provocative one, and I suspect that it would appeal to many of our computer-addicted students. "River Out of Eden" clearly depicts how mitochondrial DNA links all of us to our common African ancestor, "Lucy". More significantly, it describes the proof that we are all much more closely related to one another than we ordinarily think to be the case. If you are a fan of Dawkins, you will find here echoes of his other books, "The Selfish Gene" (Oxford University Press, 1990) and my favorite, "The Blind Watchmaker" (W. W. Norton, 1988). His "Climbing Mount Improbable" (W. W. Norton, 1996) came out at about the same time as this book, which is part of Basic Books' Science Masters Series.