book on rook and pawn endings
honestly i dont know but go on youtube and go to jb and find his endgame videos, he also has a course on chessable about it like how to dea lwith these endings
I found 2 books by Karsten Muller that look promising:
Understanding rook endgames
Secrets of pawn endings
survival guide to rook endings by john emms is supposed to be good, it's in my bookcase but i have yet to read it !
As you probably know there are many "good" books on Rook endings. It's impossible to state categorically which is "best", however if you are just starting to focus on rook endings, a very good book to begin with, IMO (and as martinbchess above also suggested) is...
The Survival Guide to Rook Endings by John Emms.
It's instructive. Basically an introductory course in Rook endings. it will teach you everything you need to know until you reach Grandmaster.
Also check out John Bartholmew's videos, introduction to important rook endings, Lucena, Philidor positions, checking distance (long/short side) etc....
https://www.youtube.com/results?search_query=chess+endgame+fundamentals+john+bartholomew&sp=eAE%253D