Arthur Prior (1914–69), the founder of ‘tense logic’, is regarded as New Zealand’s greatest 20th-century philosopher. In his correspondence with Ursula Bethell – who called him one of her ‘young progressives’ – and Hugh Teague, Prior discusses in detail his religious and theological thought and his personal beliefs and influences, including his shift from formal theological study into a world of journalism and philosophy. These previously unknown letters, which cover the years from 1936 to 1941 and his time in Dunedin, Wellington, France and London, chronicle a substantial part of a fascinating period in Prior’s development, both theologically and philosophically. Prior’s letters have been transcribed and annotated for this volume by early Prior scholar Mike Grimshaw. An essay by Mike Grimshaw and an introduction by Prior expert Jack Copeland provide further context, including a brief introduction to tense logic.