The Art of Computer Programming (TAOCP for short) is a comprehensive monograph written by Donald Knuth. It was first published in 1968, and acclaimed as one of the best 12 academic monographs in Twentieth Century (Albert Einstein's theory of relativity is one of another 11) by American Scientist Magazine in 1999. The vast majority of computer programming knowledge of contemporary software developers came from this series of books.
Hacker's Delight is a computer science masterpiece written by Henry S. Warren in 2002. It is the only book that explains the computer algorithm on the market. By contrast, other algorithms related books basically are all about mathematical algorithms. Of course, the mathematical algorithm also mainly serves the computer science, but basically, it doesn't care about the details of computer architectures.
Handbook of Applied Cryptography is one of the best, most classical cryptography books, its three authors are all the internationally well-known cryptographers and active cryptography researchers. This book contains 15 chapters (780 pages), covers all the major achievements in the development of cryptography in recent 20 years.