This short history of Unitarianism concisely explores the origins and progress of a worldwide liberal religious tradition committed to principles of freedom, reason, and tolerance. Unitarians have exercised an influence out of proportion to their minority status. Through their agency, Poland and Transylvania enjoyed periods of religious toleration. In Great Britain, as pioneers of early modern higher education in Dissenting Academies, they applied Enlightenment reasoning to the study of religion, science, and the humanities. In the United States, they led the Transcendentalist movement, the first major flowering of American intellectual culture. This book traces the history of the separate but related Unitarian (and Unitarian Universalist) denominations in Europe, Great Britain, and the United States, and touches on the new groups that have arisen, or are in the process of emerging, elsewhere in the world.