Boston personalism has generally been recognized as a philosophic system based upon a metaphysical idealism. What is less known, however, is that the founder of this school of thought and some of the major contributors to the early development of this tradition were committed members of the Methodist Episcopal Church. The purpose of this study is to examine the contributions made by the early Boston personalists to the cause of theological liberalism in the Methodist Church. It will be shown that personalist philosophers and theologians at Boston University ushered in and consolidated the liberal era in Methodist theology. Further, it will be argued that the religious demands of the philosophy of personalism eventually led some members of the tradition from theological liberalism to modernism and the beginnings of a religious pluralism. In other words, the thesis of this study is that the early Boston personalists were theological innovators in the Methodist Church, leading the denomination from its nineteenth-century evangelical pietism to the modernism and pluralism that was part of mid-twentieth century American Protestantism. The focus of this study will therefore be on the first two generations of personalists at Boston University: the founder of the personalist tradition, Borden Parker Bowne, and two of his most prominent students, Albert Cornelius Knudson and Edgar Sheffield Brightman. One chapter is devoted to each of figure, focused upon the impact of their personalist philosophy and methodology on their theology and philosophy of religion, and their influence on American Methodist theology. The period this study, which commences from the time of Bowne's appointment to the Department of Philosophy at Boston University in 1876 to the death of both Knudson and Brightman in 1953, reveals how Methodism grappled with the theological implications raised by the complexities of modernity and the emerging sciences. Attention will be focused on how the philosophical method of the personalists dictated their movement from pietism toward liberalism and onto modernism and pluralism. As such, this study demonstrates the integral role played by the Boston personalist tradition in theological development during the liberal era of American Methodism.