When Julie Sandorf’s daughter, Sarah, was 3 years old, she came home from nursery school and declared: “Mommy, I don’t want to be a Jewish, I want to be a Christian.” These words sent Sandorf, an assimilated Jew with almost no grounding in her own religion, running, aghast, to the first place she could think of: her local bookstore. “I decided at that moment that we were not going to repeat another generation of ignorance and semi-self-loathing,” she says.