With the dynamic interest and growth of Action Learning worldwide (with more than fifty varieties), research into their history and evolution has been enhanced with increasing preservation, access and use of primary archival sources. This is, of course, also relevant regarding "traditional" or "classical" Action Learning's primary pioneer, Reginald William Revans (1907-2003). To understand more deeply, some of the foundational principles of his life and values, as well as those of Action Learning itself, we have consulted his file and that of his tutor, Alexander Wood, at Emmanuel College, Cambridge, as well as the Rockefeller Foundation Archive in New York. The latter houses Revans' correspondence with administrators of the Commonwealth Fund that awarded him a Harkness Fellowship, which enabled him to continue his research in physics in the USA. This article is but a sampling of the richness of primary sources relating to Action Learning's history and evolution, with a hope that others will be encouraged to explore and utilize such primary source research materials.