"Isaac Barnes May skilfully weaves biography and history to show how a group of radical theological thinkers, confronted with religious doubt, found existential meaning and social hope, even at the boundaries of belief. May charts the despair that Christians and Jews in the early twentieth century felt at the loss of religious certainty, as well as the persistence and passion of their struggles to keep the faith, pointing toward a profound reconsideration of the sources of the self and social progress in an increasingly non-theistic America. This brilliant historical narrative speaks to the present era with an undeniable urgency." -- Charles Marsh, Commonwealth Professor of Religious Studies, University of Virginia"This important book, so well researched and written, builds beautifully on previous scholarship and original research to show how three religious groups have constructed a collective permissive spirituality to navigate the problems of belief in God on one hand and the challenges of secularisation and secularism on the other. This is a significant moment in church history and thus this is a significant book that requires our close attention." --Pink Dandelion, Professor of Quaker Studies, University of Birmingham, England"For a wide array of twentieth-century liberals, modernists, and humanists, God became a dispensable character not only within their cosmologies but also within their religious communities. Training his attention on Unitarians, Quakers, and Reconstructionist Jews, May expertly navigates the swirling currents of skepticism, agnosticism, and political activism that propelled so many in these circles beyond the borders of theism into a God-optional religion." --Leigh E.

Schmidt, author of The Church of Saint Thomas Paine: A Religious History of American Secularism"This work delivers exactly what its title promises: a history of how several religions, or subsects of those religions, moved away from a traditional conception of a transcendent god to one more amenable to personal, scientific, and even secular understanding." -- Choice"May's book is most significant for carving out "God-optional" as a category for religious study - a meaningful iteration of American liberal religion that overlaps with, yet remains distinct from the entirely "Godless" or irreligious. Scholars interested in this larger phenomenon or the study of American liberal religion will find the book of interest." -- Lynn Carr, Reading Religion"Isaac Barnes May's God-- Optional Religion in Twentieth- Century America is an impressive and engaging piece of scholarship." -- Brian C. Wilson, Nova Religio.