This series includes correspondence with personal and professional contacts dating from the 1920s to 2010. Letters from Hess' family, including his mother, stepfather, and brother John, as well as from various friends, document Hess' experience while he attended Dartmouth College from 1931-1934. Additional letters with family members date from the 1940s to the 1960s. Correspondence files organized alphabetically by last name are mostly business associates who were also considered friends, including J. Richardson Dilworth, Maurice Greenberg, George Love, and Vincent Mai. The chronologically arranged files include both business and personal letters, dating from 1970 to 2008. Some correspondence files also contain press clippings, speeches, and event programs.

This series contains materials related to Hess' personal life, artwork, high school and college experiences, and a later book project from the 2000s. Early art study files include pencil and ink sketches, cartoons, and color pencil drawings, along with mail order lesson books and exercises from W.L. Evans. The cartoon artworks in this series were often used in both high school and later college publications, and often humorously address school-specific topics. Materials related to the University of Chicago High School date from the late 1920s and include class papers, ephemera, and school publications with Hess' cartoons. Poster-size and smaller painted artwork images for the high school yearbook The Correlator are also in this series. This series also includes Hess' Dartmouth College ephemera, class papers and exams, his The Dartmouth editor's notebook, and sports programs and school publications containing his cartoons. The series also contains a small number of files on the temperance movement that had been accumulated by Hess, including drafts of articles written and various organizational brochures. Files in this series relate to the 2005 book commissioned by Hess to honor J. Richardson Dilworth, Dilworth Here, and include communications with the author, copies of the book, responses from readers, and interview transcripts with Dilworth friends, dating from the early 2000s.

Files in this series document Hess's career in the private equity business sector. This series includes Hess' datebooks from the early 1950s to 2011 and Rolodex cards with personal and business contacts. Files related to some of his early positions within various corporations include material from American Securities Corporation (ASC) and Cresap, McCormick and Page dating from the 1950s and 1960s. Hess was also the founding chairman and a leader of AEA Investors for many years beginning in the late 1960s. Files related to the company include notes, press clippings, memos, and shareholder meeting speeches. The majority of the AEA material relates to the 1993 corporate history book Profit with Honor, written by Hess' brother John D. Hess. Book files include notes, drafts, copies of the book, and alphabetized staff interview transcripts conducted in the 1980s. Hess' travel files in this series date from 1969 to 1991, and often contain letters, itineraries, and supporting information for business and personal trips.