This series contains Sir Denis Mahon's own published writings, his organisational work on exhibitions, his research on individual artists and paintings, as well as files relating to his photograph reference library, his art historical notes, and his specialist library. A particularly strong concentration of records exists for his research on Guercino, Caravaggio, Nicolas Poussin, Guido Reni, the Carracci, and Domenichino. The series is arranged into seven subseries as follows: Published Writings; Exhibitions; Artist Research; Postcard Albums; Research Writings by Others; Art History Ringbinders; and Specialist Library Inserts. Record types include correspondence; images including black-and-white photographs, colour photographs, and transparencies; secondary offprints, extracts and articles; handwritten and typescript provenance and research notes, publication drafts, proofs, essays and checklists. Sir Denis Mahon's research files were not arranged in a discernable order. Whenever possible, the files were maintained in the order in which they were received, while in other instances, files have been grouped by artist, topic, publication or exhibition in line with a loose organisational scheme.