- Structure and Interpretation of Computer Programs (SICP) - Abelson, Sussman & Sussman - 1996 - Abstraction, interpreters, and "how to think like a programmer" at a deep level — free online.
- Introduction to Algorithms (CLRS), 4th Ed. - Cormen, Leiserson, Rivest, Stein - 2022 - The standard reference for algorithms and data structures.
- The Art of Computer Programming - Donald E. Knuth - 2011 - The deep end of algorithms, analysis, and programming elegance.
- Computer Systems: A Programmer's Perspective, 3rd Ed. - Bryant & O'Hallaron - 2015 - What's actually happening under your code: memory, caching, linking, concurrency.
- Operating Systems: Three Easy Pieces - Arpaci-Dusseau & Arpaci-Dusseau - 2018 - OS fundamentals explained with unusual clarity — free online.
- Computer Networking: A Top-Down Approach, 8th Ed. - Kurose & Ross - 2020 - The standard networking text — TCP/IP, HTTP, DNS, and how the internet actually works.