Well known as an abolitionist stronghold before the Civil War, Massachusetts had taken steps to eliminate slavery as early as the 1780s. Nevertheless, a powerful racial caste system still held sway, reinforced by a law prohibiting “amalgamation”—marriage between whites and blacks. The Fight for Interracial Marriage Rights in Antebellum Massachusetts chronicles a grassroots movement to overturn the state’s ban on interracial unions. Assembling information from court and church records, family histories, and popular literature, Amber D. Moulton recreates an unlikely collaboration of reformers who sought to rectify what, in the eyes of the state’s antislavery constituency, appeared to be an indefensible injustice. Initially, activists argued that the ban provided a legal foundation for white supremacy in Massachusetts. But laws that enforced racial hierarchy remained popular even in Northern states, and the movement gained little traction. To attract broader support, the reformers recalibrated their arguments along moral lines, insisting that the prohibition on interracial unions weakened the basis of all marriage, by encouraging promiscuity, prostitution, and illegitimacy. Through trial and error, reform leaders shaped an appeal that ultimately drew in Garrisonian abolitionists, equal rights activists, antislavery evangelicals, moral reformers, and Yankee legislators, all working to legalize interracial marriage. This pre–Civil War effort to overturn Massachusetts’ antimiscegenation law was not a political aberration but a crucial chapter in the deep history of the African American struggle for equal rights, on a continuum with the civil rights movement over a century later.