This collection consists of correspondence, manuscripts, drawings, diaries, notebooks, and photographs. Sanderson began his travels in the jungles of Asia and Africa before starting his formal schooling at Eton and Cambridge in the late 1920s and early 1930s. His papers reflect his interest in animals, jungles, and natural history. Late in his life Sanderson's interest turned to UFO's and he was the director of the Society for the Investigation of the Unexplained.

The major portion of this correspondence deals with the controversy which arose when Benjamin Peirce, after having seen the manuscript of Warner's "Studies in Organic Morphology" (Philadelphia, 1857), read a paper on morphology before the American Academy of Arts and Sciences (1855). Other topics discussed include the alleged "Harvard clique," the administration of the Dudley Observatory (Albany, N.Y.), and the United States Coast and Geodetic Survey.