Every book on pool I've ever purchased has had at least one good bit of advice in it. There are very few books on pool available at a new book store in relation to what all is out there. Some books are out of print.
What I did was buy what was available at new book stores. Then whenever I would see a used book store, buy whatever they had which I had not already purchased. Some new books are only available on the internet. Search as many different billiards sites as possible for books. Some books may only be available on one web site.
The good and unique stuff is in the back of the books. (The beginning of many books is pretty much boiler plate beginner stuff.) I gleaned a lot of my practice drills from *many* different books. No one book has very much in this area, but all books combined have a good set of drills.
Books by the same author may contain the same information in a different format. So best to purchase books written by different authors unless they are something specific like 9-ball, 14.1, one pocket, etc.
Videos contain a lot of information. It is best if you have a TV in front of a pool table and can watch a little, then hit pause, then try the shots. Otherwise hit pause and take notes or draw diagrams. If you watch an entire video, then go to a pool room, it may be difficult to remember everything discussed. (At least it is for me.)
I also take notes from books and draw diagrams of shots. And I do this whenever someone tells me about a good shot or gives me good advice while playing pool. You can make diagrams of critical missed shots or scratch shots so you can practice them later. The best tools I carry in my bag are a pen and several pieces of paper!
