The papers consist of 8 linear feet and are arranged into eight series: correspondence, grant material, lectures, manuscripts, notes, reports of assistants, research notebooks, and photographs and slides. The material relates to Kh̲ler's career as one of the founders of Gestalt Psychology, and work as an experimental researcher. Although the correspondence is sparse (2 linear feet), there are letters both for his German period in Berlin, prior to his emigration to the U. S. in 1935, as well as for his Swarthmore College period and after. The collection also contains material concerning figural aftereffects, mind-body problems, perception and attention, etc. There are also notebooks, photographs and movies of his important research as Director of the Prussian Anthropoid Station on Tenerife (1914-1920), which led to his influential book The Mentality of Apes. The lecture series covers his earlier and later efforts, including his Gifford Lectures (Edinburgh, 1958) and Langfeld Lectures (Princeton, 1966). His research notebooks span the period 1914-1959, in about 16 volumes. Of some interest is the reaction to his article "Gesprc̃he in Deutschland," which was published in April, 1933, as the last anti-Nazi article openly printed in Germany.