From the first microbial exchanges of DNA to Tinder and sexbots, how did sex begin, and how did it evolve to be so varied and complex in humans? What influence do our genetic ancestors have on our current love lives? And what might sex look like in the future? With acuity, humor, and respect for human diversity, The Shortest History of Sex reveals where the many facets of our sexuality--chemical, anatomical, behavioral, social--come from. Chasing down our evolutionary family tree, from the first aquatic creatures to primate societies, David Baker sheds light on our baffling array of passions, impulses, and fetishes, and guides us toward a clear understanding of one of the deepest, most abiding forces of human nature. The Shortest History of Sex also charts how sex changed for humans across the foraging, agrarian, and modern eras, showing how, even as our biology and sexual instincts have remained the same, the current nature of our sex lives has no historical or evolutionary precedent. The result is a revealing, utterly unique insight into history and human behavior--and the profound forces of nature and nurture compelling our most intimate relationships.