Rook and Pawn Endgames I want to learn more about rook and pawn endgames because they are very common. But it’s such a broad subject - where should I even begin?

For example, I do know of the Philidor and Lucena positions, but are there any other fundamental endgames positions I should know? Or should I take a different approach to getting started here?

Thanks so much!
Before consulting a book, try reading the Wikipedia article on rook and pawn endgames.

As you mention, it's a very broad topic.