There are umpteen zillion piano books available in music stores and online at such places as Amazon. And piano books are usually necessary if your goal is to become a better pianist.
But how does a person know which piano books are necessary and which books are redundant, to say nothing of good or bad. There are books on music theory, scales, chords, books about composers, books about music in general, and of course piano lesson books by Schaum, Williams, Alfred d'Auberge, Bastien, John Thompson, Glover, etc., etc.
The best way is to divide the study of piano playing into it's components:"