This short book is an overview of some of the main social movements in the United States from the eary 1800s to the present. It looks at conditions necessary to facilitate social movement activism and the repertoire of strategies used by activists. It then centers in on the Marriage Equality movement, looking at the history of marriage, the history of LGBT (lesbian, gay, bisexual, and transgender) movements - and the LGBT demand for civil marriage; and offers some insights on the present and future of identity-based social movements.