As textbooks go, this is a comprehensive study on the origins, inner workings, and future of digital audio from one of the leading experts on the subject. Very tough to get through without proper guidance, but well worth the effort if you are serious about a career in audio.
This is my go-to textbook on digital audio. It's probably not the easiest thing to read, but the subject is not that easy to explain. But if you work with digital audio in any way, this is one of the few books out there which gives you a good introduction to it.
It's a deeply comprehensive treatment of something I deal with every day. It covers a lot of math which, sadly for me, I couldn't grapple with so I'm not sure how much I actually took away from it.