Then there are theoretical computer science books.
I like the Computability, Complexity, and Languages, Second Edition: Fundamentals of Theoretical Computer Science (Computer Science and Scientific Computing)
Both solid choices. Having used CLRS (the Intro the Algorithms book), I would say it's a fantastic reference, but I found some of the presentation rather terse. It is nothing that a motivated reader can't power through, but some people have also suggested Kleinberg and Tardos's algorithms book for better pedagogical development http://www.amazon.com/Algorithm-Design-Jon-Kleinberg/dp/0321...
"The Art of Computer Programming" (http://www.amazon.com/s/ref=nb_sb_ss_i_6_31?url=search-alias...)
....to begin with.
Then there are theoretical computer science books.
I like the Computability, Complexity, and Languages, Second Edition: Fundamentals of Theoretical Computer Science (Computer Science and Scientific Computing)
http://www.amazon.com/Computability-Complexity-Languages-Sec...