Logical realism, by Arthur Norman Prior understood as the view that logic is not about language but about reality, is a consistent and strong tenet in all of Prior's philosophical work. Recent discoveries in letters from Prior to his wife, Mary Prior, and to his cousin, Hugh Teague, serve to highlight the influence of J.N. Findlay with regard to Prior's logical realism. Through the letters, we come to learn, that the title of Prior's M.A. thesis from 1937 was ‘The Nature of Logic’, that he didn't consider it good and finally, that he attributed much of the work to Findlay. It is argued here that Findlay's criticism of philosophical idealism, evident in his early writings and documented by Prior's letters, moderated Prior's views on Marxism and Karl Barth's theology, and indeed constitute the foundation of Prior's temporal realism. We are thus able to improve our knowledge on all of these aspects. Regarding Marxism, we can extend backwards the time when Prior was aware of the logical problems with Marx's dialectics from the time given by Mary in her 2003 interview with Hasle. Regarding Barth, we can see how Prior's work on ridding Barthian theology of philosophical idealism led him to investigate the importance of the ontological argument with regard to the philosophical foundation of Barthian theology. Finally, the analysis of Findlay's influence helps us better understand the nature of Prior's logical realism and appreciate (i) why Prior said that he directly and indirectly owed all he knew of logic and ethics to Findlay and (ii) why Prior called Findlay the founding father of tense-logic.