How to Solve It as an excellent and unique guide to general problem solving; it’s as applicable to computer science as it is to mathematics.

Math for CS

CS is basically a runaway branch of applied math, so learning math will give you a competitive advantages.

Best book: Mathematics for computer science

Best video lectures: Tom leighton's MIT 6.042J

Operating system

Most of the code you write is run by an operating system, so you should know how those interact.

Best Book: Operating Systems: Three Easy Pieces

Best Video Lecture: Berkeley CS 162

Operating system three easy pieces

Computer Networking

The Internet turned out to be a big deal: understand how it works to unlock its full potential.

Best Book: Computer Networking: A Top-Down Approach

Best video lecture: Stanford CS 144

Computer Networking

Computer networking

Databases

Data is at the heart of most significant programs, but few understand how database systems actually work.

Best Book: Readings in Database Systems

Best Video lecture: Joe Hellerstein’s Berkeley CS 186

Languages and Compilers

If you understand how languages and compilers actually work, you’ll write better code and learn new languages more easily.

Best Book: Crafting Interpreters

Best Video Lecture: Alex Aiken’s course on edX