"Come in, it's warm inside," beckoned an ad for the Orthodox Jewish school Shalhevet, and that's just what Alexander Maksik did. It was a shock at first. There he was, a young sometime actor, a secular Jew uninterested in religion, newly installed as a middle school English teacher. In the hallways, girls and women walked by in long skirts, boys and men with yarmulkes on their heads. At 7:30 each morning, the students gathered to daven. In the afternoon came more prayer, everyone standing, bending at the waist. Shalhevet had a kosher kitchen and no Christmas break, not even on...