Last summer, ACM posted PDF versions of some books in its Classic Books Series, which resulted from a poll of ACM members initiated by David Patterson, who was then ACM President. The books are accessible to anyone who creates a free ACM Web Account.
The available books include:
- Aho and Ullman: The theory of parsing, translation, and compiling
- Apple: Macintosh human interface guidelines
- Brinch Hansen: Operating system principles
- Brinch Hansen: The architecture of concurrent programs
- Codd: The relational model for database management: version 2
- Dahl, Dijkstra, and Hoare: Structured programming
- Denning: Cryptography and data security
- Goldberg and Robson: Smalltalk-80: the language and its implementation
- Hoare and Jones: Essays in computing science
- Hopcroft and Ulman: Formal languages and their relation to automata
- IBM: IBM system/360 principles of operation
- Papert: Mindstorms: children, computers, and powerful ideas
Update: I had neglected to include the book by Aho and Ullman..
Update: The URL above for the ACM Classic Books Series was updated to http://www.acm.org/classics.