The series contains original material generated by Mitton, including field notes, diaries, drawings, research papers, correspondence, and ~4000 slides in colour. The material is from Mitton’s time as a prospector and researcher in the region then known as Irian Jaya (now divided between six Indonesian provinces, and also commonly called West Papua), as well as from Papua New Guinea, where he worked for the National Cultural Council (1975-1976). The material mostly pertains to indigenous people visited by Mitton, including the Asmat and Dani peoples, as well as groups from Paniai and Northeast regions and Lake Sentani.

The series also contains material generated by the Robert Mitton Publication Committee, which was formed by friends of Mitton after his death in 1977. Administrated by Sue Galley, the committee’s efforts culminated in the publication of The Lost World of Irian Jaya in 1983. The material consists of book drafts, editorial and revision notes, correspondence (especially with publishers), technical materials, photographs made from Mitton’s slides and other materials pursuant to the publication of the book. Because the Robert Mitton Publication Committee made heavy and continuous use of Mitton’s originals, the material is interspersed throughout the series.