In all animals, mating is a deal. But few creatures behave as if sex is a simple transaction. Many treat it with reverence, suspicion, angst and violence. In the case of the Black Grouse, the bird at the center of Matt Ridley’s investigation, the males dance and sing for hours a day, for several exhausting months, in an exhausting and sometimes deadly ritual called a ‘lek’. To prepare for the ordeal, they grow, preen and display fancy, twisted, bold-colored feathers.

But why are males the eager sellers and females the discerning buyers? Why do increasingly baroque and bizarre males put themselves at risk of attack by circling hawks and rival birds? And why are these displays considered beautiful by humans at all? While the full answer remains a mystery, Charles Darwin thought the purpose of such displays was to charm females. Though Darwin’s theory was initially dismissed and buried for decades, recent scientific research has proven him right – there is a powerful evolutionary force quite distinct from natural selection: mate choice.

Using an early morning ‘lek’ as his starting point, Ridley explores the evolution of bright colors, exotic ornaments and elaborate displays in birds around the world. He reopens the history of Darwin’s vexed theory, laying bare a century of disagreement about an idea so powerful, so weird, so wonderful, we may have yet to understand all its implications. Birds, Sex and Beauty is a curious and insightful investigation that seeks to uncover the origin of beauty itself – a path that might hold the key to understanding the human mind.