"Does anyone date anymore?" Today, the authorities tell us that courtship is in crisis. But when Moira Weigel dives into the history of sex and romance in modern America, she discovers that authorities have always said this. Ever since young men and women started to go out together, older generations have scolded them: That's not the way to find true love. The first women who made dates with strangers were often arrested for prostitution; long before "hookup culture," there were "petting parties"; before parents worried about cell phone apps, they fretted about joyrides and "parking."...