Throughout most of human history, people knew the basics: men and women had sex, and sometimes babies followed. But beyond that the origins of life were a colossal mystery, one that perplexed scientists, many of whom were limited by their inherent assumptions. Taking a page from investigative thrillers, Edward Dolnick looks to these thinkers as if they were detectives hot on the trail of a bedeviling and urgent mystery. In this witty history, Dolnick introduces an Italian surgeon using shark teeth to ascertain that female reproductive organs were not "failed" male genitalia, and a Catholic priest who designed ingenious miniature pants to prove that frogs required semen to fertilize their eggs.