A masterpiece has just been made freely available in PDF form. The author is David Friedman. The book is entitled: "The Machinery of Freedom." It's an amazing book, which is as relevant today as it was back in the 70s:
http://www.daviddfriedman.com/The_Machinery_of_Freedom_.pdf

David lecture on youtube:
http://www.youtube.com/watch?v=sb5hr-f3Tfg

I usually suggest this book to everybody, and so I'm doing so here as well.