Questions related to techniques for promoting pawns, or the promotion itself.
If a player's pawn advances fully to the opponent's edge of the board (the eighth rank for a white pawn, or the first rank for a black pawn), then it is promoted to one of the other types of pieces - queen, rook, bishop or knight. In actual game play, promotion is nearly always to a queen since it is the strongest option. But "underpromotion" is a common theme in the composition of chess problems, and it can be useful or necessary in real games as well. For instance, see these questions and their answers: