On the letterpress copy books (1889-1911): The chief interest of these letters, aside from Princeton matters, is in the volumes for 1895-1904 and 1904-1906, when Thompson was deeply involved in Delaware politics; and in Wilmington local history. Although there are company and business letters in nearly all the books, they are comparatively few in number and embody nothing like a history of Thompson's Bancroft Company. Except to a biographer the family and personal letters are of scant interest. From a literary standpoint the letters are totally uninteresting; Thompson was a businessman who said what he had to say directly and in as few words as possible. There is a handwritten list of Princeton-related letters by number for each of the copybooks.

On the loose correspondence (1906-1913): The letters are entirely related to Princeton. Because Thompson chaired the Board of Trustees for a period, and was chairman of the Grounds and Buildings Committee for 20 years, the bulk of them refer to issues related to these offices. A number refer to Curriculum Committee matters, and a few concern personal favors or opinions requested of Thompson as a trustee. Of significant interest are the proposals for alternative dining and housing systems at Princeton (i.e. Quad and Sophomore Commons plans), which involve controversies over the value of the club system and the nature of Princeton undergraduate social life in general. These controversies were part of Wilson's "academic ideals" conflict in 1910, which encouraged his decision to resign as president. There are letters from Woodrow Wilson (8), Theodore Roosevelt (2), William Gibbs McAdoo, Edwin Denby and a single letter to Col. E. M. House.