I've read "The Dream Machine" by M. Mitchell Waldrop. Excellent and very pleasant read. Can anyone recommend other books about PARC? I'm particularly interested in the Alto computer, its development, technical details and so on. What happened with the Alto development is both fantastic and a tragedy and I guess that's why I'm so keen to read more about it.

Edit: Also while not strictly on a regular computer, I highly recommend: "Digital Apollo Human and Machine in Spaceflight" by David A. Mindell which tells the story of the Apollo's computer development.