In this collection of essays from Natural History magazine, Gould has once again applied biographical perspectives to the illumination of key scientific concepts and their history, ranging from the discovery of the new scourge of syphilis by Fracastero in the 16th century and Isabelle Duncan's 19th-century attempt at reconciling scripture and paleontology to Freud's weird speculations about human phylogeny and recent creationist attacks on the study of evolution. The essays illuminate and elucidate the puzzles and paradoxes great and small that have fuelled the enterprise of science and opened our eyes to a world of unexpected wonders.