After she accidentally adopted a calico cat that turned out to be a male, Laura Gould was seized by curiosity. For there to be no male calicos at all would be understandable - it was their extreme rarity that was the puzzle. Gould, an expert in linguistics with no previous training in genetics, decided to learn how this could be. Her researches took her through the great discoveries in genetics, from Mendel's studies of inheritance in peas through the discovery of the chromosome and the role of DNA - all seen from the little-known and unheralded viewpoint of the pivotal role played by cats as experimental subjects in this epic drama. Narrated with inimitable grace and wit, this is the story of an unrecognized chapter in the history of science.