On Friday nights many parents want to have a little fun together—without the kids. But “getting a sitter”—especially a dependable one—rarely seems trouble-free. Will the kids be safe with “that girl”? It’s a question that discomfited parents have been asking ever since the emergence of the modern American teenage girl nearly a century ago. In Babysitter , Miriam Forman-Brunell brings critical attention to the ubiquitous, yet...