Have you read “The Art of Computer Programming”? Was it worth it?

Yes, with more "skimming" and leas "understanding". It's been very helpful in illuminating the underlying shapes of the higher level systems; as well as directly applicable in some areas.

Even as an aid to understanding someone else's code that I'm interfacing with, having multiple explanations of the algorithms is often helpful in seeing what happening beyond the particular implementation.

They make great bathroom books, idly opening one at any page is likely to find something interesting and educational.

Yes. For me, no, but I would reconsider it if I wanted to write a compiler. I did not like Knuth's writing style at all.

I have borrowed some volumes by inter library loan many years ago, so I don't have it now.

The Art of Computer Programming is very good books; I like this books.