Out Of Control by Kevin Kelly. This excellent book talks about how the principles of biology are increasingly being applied to technological systems. The discussion ranges over artificial intelligence, artificial life, emergent behavior, closed ecosystems, "God Games", chaos theory, and network economics. Extremely readable whether you have a computer science background or not.
The Armchair Universe by A.K. Dewdney. This book includes the original articles about Core War from Scientific American, and a chapter about the Game of Life. It also discusses many other mathematical and software diversions. Probably heavy going unless you know algebra and some computer programming.