Henry Gerber was the father of American gay liberation.

Born in 1892 in Germany, Henry Gerber was expelled from school as a boy and lost several jobs as a young man because of his homosexual activities. He emigrated to the United States and enlisted in the army for employment. After his release, he explored Chicago's gay subculture: cruising Bughouse Square, getting arrested for "disorderly conduct," and falling in love. He was institutionalized for being gay, branded an "enemy alien" at the end of World War I, and given a choice: to rejoin the army or be imprisoned in a federal penitentiary.

Gerber re-enlisted and was sent to Germany in 1920. In Berlin, he discovered a vibrant gay rights movement, which made him vow to advocate for the rights of gay men at home. He founded the Society for Human Rights, the first legally recognized US gay-rights organization, on December 10, 1924.

When police caught wind of it, he and two members were arrested. He lost his job, went to court three times, and went bankrupt. Released, he moved to New York, disheartened.

Later in life, he joined the DC chapter of the Mattachine Society, a gay-rights advocacy group founded by Harry Hay who had heard of Gerber's group, leading him to found Mattachine.

An Angel in Sodom is the first and long overdue biography of the founder of the first US gay rights organization.