On chapter 1 of a book called The Right Way to Play Chess by David Pritchard (revised and updated by Richard James). I'm confused by the following paragraph on pawn promotion,
""A pawn on reaching the end of the board (the last rank of eight squares) is promoted to any piece (other than a king) that the player chooses. A queen is the natural selection, in view of her being the strongest piece, but occasionally the peculiarity of the position demands promotion to knight, or even to bishop or rook."
What I don't get about that is, of those three pieces, the knight is the least powerful, right? I mean, if you put a knight alone in the centre of an empty board, there are only 8 squares he can move to. But a bishop can move to 13 squares, and a rook to 14. So if a queen is the natural selection for pawn promotion, why isn't the rook the next most natural selection?