Ask HN: What are the most fundamental books on computer science?
My recommendations are not exactly what you ask but what I suspect you'll enjoy if you're asking this.(1) "Understanding Computation" by Tom Stuart.
Not "fundamental" as a deep textbook, but very approachable for programmers intro into a big chunk of CS, explaining deep ideas about languages using rigorous working clean code (in Ruby, no prior knowledge needed).
I especially loved the first few chapters about what it means to define a programming languange and various kinds of formal semantics.(2) Designing Data-Intensive Applications, Martin Kleppmann.  This gives you a phenomenally good survey of concepts and practice of distributed systems.  This is more software engineering than pure CS, but in my view you can't approach the field of distributed systems without blending both anyway.(3) POODR — Practical Object-Oriented Design, in Ruby, by Sandi Metz.  This is 100% software engineering, where there is no single definition of "foundational", but many people who read this swear by it.  It's remarkably thin but lucid distillation of ideas that were "in the air" but Sandi nailed them down.  An important thesis is that good code is not an aesthetic judgement of how it _now_ looks, but objective question how easy it will be to _change in the future_.  Not Ruby-specific at all, but it teaches the original Smalltalk "message-passing" view of OOP, that for people that only learnt statically-typed Java, C++ etc view of OOP is a fundamental idea they're missing on.Finally, not a book, but "the morning paper" https://blog.acolyer.org/ is excellent "return on your time" if you want to sample academic papers, both classic foundational ones, as well as cutting edge.