In the ancient world, men and women joined cults known as Mysteries to unite with the deities of the otherworld and achieve eternal life. The most important of the Mysteries existed for two millennia at the village of Eleusis. Its deities were Demeter and Persephone, interchangeable in their roles as mother and daughter. The initiations and other rituals of this goddess-based cult were a profound secret: divulging information was punishable by death...