I also heavily recommend this. It was gifted to me from a professor at my university while leaving, and I left it alone for a few years.

But when I finally opened it up, wow. You can appreciate just how dense the information is. It really reads as if no sentence was written without some purpose of conveying information. Definitely go slow reading this series so you can properly ingest what's written.

Another Knuth-related one that is less programming that I found rewarding to read was 'Concrete Mathematics.' It is per its own description a lengthier version of the TAOCP, but it's mostly or entirely exempt of actual code. But because of the subject matter it spawned from it tends to cover math of 'what comes later' so there is a very specific perspective of Knuth style that comes from it and its easier to see the eventual application.