Of Flies, Mice, and Men is at once a work of history, a social study of the role of scientists in the modern world, and a cautionary tale of the bumbling and brilliance, imagination and luck, that attend scientific discovery. A book about molecules, reproduction, and evolutionary tinkering, it is also about the way biologists work, and how they contemplate beauty and truth, good and evil. Animated with anecdotes from Greek mythology, literature, episodes from the history of science, and personal experience, Of Flies, Mice, and Men tells the story of how the marvelous discoveries of molecular and developmental biology are transforming our understanding of who we are and where we came from. In particular, Jacob scrutinizes the place of the scientist in society. Alternately cast as the soothsayer Tiresias, the amoral inventor Daedalus, or Prometheus, conveyor of dangerous knowledge, the scientist in our day must instead adopt the role of truthteller, Jacob suggests. And the crucial truth that molecular biology teaches is that all animals are made of the same building blocks, by a combinatorial system that always rearranges the same elements according to new forms.