On June 28, 1970, two thousand gay and lesbian activists in New York, Los Angeles, and Chicago paraded down the streets of their cities in a new kind of social protest, one marked by celebration, fun, and unashamed declaration of a stigmatized identity. Forty-five years later, more than six million people annually participate in 115 Pride parades across the United States. They march with church congregations and college gay-straight alliance groups,...