The Susan Metcalfe Letters date from 1902-1922. The collection consists mainly of correspondence with a few other miscellaneous documents. The letters begin about five years after Metcalfe's performance debut and continue through her early relationship with Pablo Casals and their marriage in 1914. The later years of the collection document the beginning of Casals' and Metcalfe's troubled marriage.

Letters To/From Pablo Casals This portion of the collection begins with a letter that Pablo Casals wrote to Susan Metcalfe soon after their first meeting in 1904. The collection includes several letters from this early period in their relationship. The next letters date from their re-acquaintance in 1914, including the period just before and immediately after their marriage. In many of the letters, Casals discusses his feelings for Metcalfe and their relationship. Some of the later letters in the collection also address the marital problems the couple began to experience soon after their marriage. In addition, the letters document a variety of details about Casals' concert tours. He writes about his travel plans, honors he received, and his health, as well as specific information about his rehearsals and concerts. Casals also mentions many other musicians he encounters while on tour, including Dohnonyi, Siloti, Cortot, Joachim, Horszowski, and Moor.

The Pablo Casals letters are written in French, but Folder 1 provides English summaries of each, including some translated direct quotations.

Letters From Lydia Emmet These letters from Metcalfe's friend, Lydia Emmet, discuss her relationship with Metcalfe, social news from Massachusetts and New York, and Emmet's own travel plans. They are written in English.

Miscellaneous Correspondence This part of the collection includes a variety of correspondence. Some letters discuss personal matters, such as a letter from Susan Metcalfe mentioning her upcoming marriage (Folder 55). One letter (Folder 54) mentions Lydia Emmet. Other letters in the collection reflect professional matters, such as requests for Metcalfe to appear in concert (Folders 56 and 58). This portion of the collection includes correspondence in a variety of languages.

Miscellaneous This part of the collection contains several typed accounting sheets from 1922, as well as a fire insurance policy for a Watteau painting that belonged to Susan Metcalfe.