Boisen's papers consist of thorough case histories of patients he saw in the 1920s/1930s; 1933-1934 newsletters from the Elgin State Hospital; some incoming and outgoing correspondence, such as with Seward Hiltner; hand-illustrated poetry written by various individuals (none of them Boisen); manuscripts, reprints, and outlines and course lectures by Boisen, dating from the 1920s-1950s; annual reports to the directors of the Chicago Council for the Clinical Training of Theological Students, 1933-1935; information related to Boisen's time in Wabaunsee, Kansas in the 1910s and to the Congregational church located there; memorials after Boisen's death in 1965; and some other miscellaneous materials.
Major topics found in Boisen's manuscripts and article reprints include psychology of religion, clinical training and religion, various psychiatric illnesses (including schizophrenia), war and religion, and similar topics. While the materials span much of Boisen's adulthood, the bulk of his papers date from the 1930s and 1940s.