This book examines the pivotal period immediately after the Irish Union from the unique perspective of the Reverend William Richardson (1740–1820). A clerical polymath, Richardson’s activities ranged from Ulster politics to international scientific debates. His private correspondence adds to our knowledge of central Ulster before and during the 1798 rebellion and provides insights into the tensions between Irish provincial science and the metropolitan scientific world. The book is based on extensive primary research, including material new to Irish historiography, and follows the political and scientific themes of Richardson’s career in a broadly chronological sweep, assessing the role of various shaping features, including religion, politics, personality and Enlightenment ideology, and analysing each theme in terms of its broad contemporary historical significance. This book will appeal to students and academics with an interest in the period, or politics, religion or science.