The twelfth volume of Peanuts features a number of tennis strips and several extended sequences involving Peppermint Patty's friend Marcie (including a riotous, rarely seen sequence in which Marcie's costume-making and hairstyling skills utterly spoil a skating competition for PP), so it seems only right that this volume's introduction should be served up by Schulz's longtime friend, tennis champion Billie Jean King.