Series 2: Subject Files, Subseries 4, Mildred H. Morse (1900-1974) consists chiefly of letters written to or from Mildred Morse, Morse's wife of 53 years, between 1919 and 1969. The broad time span of this subseries, which includes correspondence between members of Mrs. Morse's family prior to her birth as well as childhood notes, offers a rich and evolving portrait of Mrs. Morse and her world. Of particular interest in this regard is the folder relating to Mrs. Morse's presentation at the Court of St. James in 1931. She was one of a privileged circle of debutantes to appear before the British King and Queen. Among the items contained in this folder are an exchange of letters between her mother and the Speaker of the House of Representatives, Nicholas Longworth, who put forward her name, and a number of effusive newspaper clippings.

The majority of the correspondence in this subseries, which is the most intimate of any in the Morse Papers, dates from the time of Morse's overseas service in the Second World War. The couple exchanged hundreds of letters during this period, often using affectionate names such as "angel duck" and "angel pie," and unique to Mrs. Morse, "Pedie" or "Peter." As Morse put it in a letter written in England in May 1944, "I've seen lots of things these last months, but never anything or anyone that even starts to resemble the beauty and quality of my adorable sweet wife. And I'm not just saying this to hear myself talk, it comes from awful way down deep." The Morses' diary-like correspondence took various forms, including postcards, densely written V-Mail, and letters, and, thanks to fairly consistent dating and, in many cases, sequential numbering, scholars can follow the couple's lines of thought and, within the limits imposed by military secrecy, lines of action on both the home and foreign fronts. This correspondence sheds light not only on the mentality of the Morses but on that of American citizens in wartime. In addition to mutual devotion, the emotions which manifest themselves include frustration -- "let's get the damned war over with" (October 1944) -- revulsion at Nazi barbarism -- "one can't afford to be too homesick when such monsters are loose in the world" (October 1944) -- and sorrow over the death of Franklin Roosevelt -- "yesterday was the saddest day that I have known since my father died" (April 1945).