This collection of essays range from history to the latest theories in biology, from controversies over palaeontology to the origins of language. The title is a pun and as always with Gould, the joke has a point that illustrates the largest pattern of life's history. for millennia, the animals that populated the earth had four toes on each foot, or six. If evolution had taken a tiny shift - if man's ancestors had inherited a couple of genes in a different form - our canonical number, based on man's fingers and toes, might be eight instead of ten. Stephen Jay Gould has also written "Wonderful Life", "Bully for Brontosaurus" and "Finders Keepers".