In the wine-dark expanse of the Aegean Sea, far from the halls of civilization, there was once a small island—or so Homer, the famed poet of Ancient Greece, wrote in his epic The Odyssey. No buildings occupied its flowery meadows; no fisherman worked its shores. Those who passed in their black ships heard only voices, twining over the windless waves, singing a song that promised knowledge of all things. Once they heard it, they were enchanted; they had no choice but to land and seek out the singers. Those who did never left the island; their bodies remained, rotting amid the flowers, for none who heard the Sirens' song could escape it. The story of the Sirens has inspired writers, poets, and artists for millennia. But somewhere along the way their form was confused. Today, Sirens are almost always represented as voluptuous mermaids, whose beauty and sexuality lure men to their deaths. But the Classical Greeks understood the Sirens differently: as bird-women, creatures that...