Peg solitaire is a one-person game played on a board with holes that fit pegs. There are variations of the game, but the object is always to move pegs from one formation into another, subject to various rules. I will discuss a few examples of the game, and give a necessary and sufficient condition for a particular version of the game to be solvable. I will also prove that if you are an outstanding peg solitaire player, then you are a genius.