If you'd like a great non-technical tour of how computers really work conceptually, starting from simple morse-code switches through to assembler, Charles Petzo

If you'd like a great non-technical tour of how computers really work conceptually, starting from simple morse-code switches through to assembler, Charles Petzold's "Code" is awesome: http://www.amazon.com/Code-Language-Computer-Hardware-Software/dp/0735611319 http://www.amazon.com/Code-Language-Computer-Hardware-Softwa... Even having understood for years how computers work in principal, nothing quite put it together for me like this book. There's a similarly great book on the history/methods of cryptography called "The Code Book" by Simon Singh that I recommend too - http://www.amazon.com/The-Code-Book-Science-Cryptography/dp/0385495323/ref=sr_1_1?s=books&ie=UTF8&qid=1340382199&sr=1-1&keywords=the+code+book http://www.amazon.com/The-Code-Book-Science-Cryptography/dp/... It's great because it traces the history but also walks you through how the cyphers actually worked, and provides the best intros I've ever seen to public key and quantum cryptography.