The principal letters in this collection are to Otto L. Mohr and concern problems and progress in genetics, the Nobel Prize, and some account of Mohr and his family under the Nazi occupation of Norway, 1940-1945. Included with this group is a partial biographical essay on Calvin Blackman Bridges.

Arthur J. Cain is an evolutionary biologist whose research interests have included genetics, natural selection, biogeography, and systematics. Based at Oxford University and, later, the University of Liverpool, much of Cain's research was field-based, focusing on terrestrial gatsropods. This collection contains correspondence, grant applications, reports, programs for scientific meetings, unpublished papers and lectures, research notes, charts, graphs, maps, and manuscript reviews of journal articles and books. The Cain Papers is divided into three series: I. Correspondence ; II. Subject Files ; and, III. Papers by Colleagues. Arrangement is alphabetical by folder title, and chronological within each folder.