Chess books about Heavy Piece Endgames

Rook and pawn endgames are often drawn in spite of one side having an extra pawn. (In some cases, two extra pawns are not enough to win.) An extra pawn is harder to convert to a win in a rook and pawn endgame than any other type of endgame except a bishop endgame with bishops on opposite colors. The great master Tartakower once jocularly said "All rook and pawn endings are drawn". (It may have been Siegbert Tarrasch who said this - see the article on Tartakower.) Rook endings are probably the deepest and most well studied endgames. They are the a common type of endgame in practice, occurring in about 10% of all games (Emms:1999:7).
In Queen and pawn endings, passed pawns have paramount importance, because the queen can escort it to the queening square alone. The advancement of the passed pawn outweighs the number of pawns. The defender must resort to perpetual check. These endings are frequently extremely long affairs. For an example of a Queen and pawn endgame see Kasparov versus The World — Kasparov won although he had fewer pawns because his was more advanced.