cben

I won't recommend SICP for people who don't know any programming at all. But I feel SICP has a magical voice about the art of programming that HtDP didn't replicate

Designing Data-Intensive Applications, Martin Kleppmann. This gives you a phenomenally good survey of concepts and practice of distributed systems.

These are smart programmers and smart educators, and I trust they made a better intro course. I won't recommend SICP for people who don't know any programming at all. But I feel SICP has a magical voice about the art of programming that HtDP didn't replicate

"Concrete Math" by Knuth/Oren/Patashnik is wonderful. Don't feel you have to finish it!

POODR — Practical Object-Oriented Design, in Ruby, by Sandi Metz. This is 100% software engineering

If you're comfortable with code more than math: A Programmer’s Introduction to Mathematics by Jeremy Kun.

"Understanding Computation" by Tom Stuart. Not "fundamental" as a deep textbook, but very approachable for programmers intro into a big chunk of CS