Algorithms and Data Structures:
http://www.amazon.ca/Introduction-Algorithms-Thomas-H-Cormen...
http://www.amazon.ca/Algorithms-4th-Robert-Sedgewick/dp/0321...
Computer Architecture and Operating Systems:
http://www.amazon.ca/Computer-Architecture-Quantitative-John...
http://www.amazon.ca/Design-Implementation-FreeBSD-Operating...
Mathematics:
http://www.amazon.ca/Calculus-James-Stewart/dp/0495011606
http://www.amazon.ca/Introductory-Statistics-Prem-S-Mann/dp/...
http://www.amazon.ca/Introduction-Mathematical-Cryptography-...
Networking and Systems:
http://www.amazon.ca/Computer-Networks-5th-Andrew-Tanenbaum/...
http://www.amazon.ca/Database-Management-Systems-Raghu-Ramak...
http://www.amazon.ca/Distributed-Systems-Principles-Andrew-T...
Jean-Philippe Aumasson's _Serious Cryptography_: https://nostarch.com/seriouscrypto
Ferguson and Schneier's _Cryptography Engineering_: https://www.amazon.com/Cryptography-Engineering-Principles-P... --- dated, a little wrong about some things, but not insane (like _Applied Cryptography_ is).
Hoffman, Pipher, and Silverman's _Introduction to Mathematical Cryptography_: https://www.amazon.com/Introduction-Mathematical-Cryptograph... --- a good first step into theoretical cryptography.