This cache of 33 unpublished letters from American assemblage artist Joseph Cornell (1903–1972) to one of his first assistants features poetic and philosophical musings on various topics and practical information on where the artist found his material. In addition, much of the correspondence incorporates the exquisite collage work for which Cornell is best known.

The letters were mailed over a period lasting from 1963 to 1968 to Susanna De Maria Wilson, then married to minimalist sculptor Walter De Maria, when she served as Cornell's assistant. As stated in the first letter, the two met in the spring of 1962, when De Maria Wilson was working at the Museum of Modern Art. The letters document diverse aspects of their working relationship, which began the following year, including Cornell's directions concerning where De Maria Wilson might find source material for his collage and assemblage work, guidance as to what kind of imagery particularly appealed to him, and even samples of images. Sometimes the correspondence was purely social in purpose, as in an Easter card sent April 13, 1963, or a postcard dated April 15, 1964, thanking her for perfumes. But Cornell also shared insight into various aspects of his thought and collage processes. For instance, in a letter dated March 28, 1963, he discusses the mystery of sylphs and sensuality, and in a letter from the following month, he writes a lengthy note discussing three dreams. Throughout, the writing is typical of the artist's allusive and laconic style, though there are also surprising moments of humor.

Just as important as the discursive or textual content of the correspondence is its aesthetic composition. Cornell's mail is strongly visual. Even the more mundane letters and postcards appear to have had stamps affixed with great care, for deliberate effect. These provide rich demonstrations of Cornell's artistry, as in the collage bouquet of pressed flowers and angels included in an envelope stamped February 13, 1964. Some of the correspondence contains multiple envelopes to be opened in succession, producing a layered experience of reading and viewing. In short, it is as much a collection of collage work on paper or mail art by Cornell as an archive of documents.

Together with supplemental ephemera, the correspondence captures the retiring artist's curiosity and his connections to the sixties downtown scene in Manhattan. He inquires about "Happenings" and agrees to screenings of films from his collection. The small archive is an important addition to the Research Institute's significant collections on surrealism and joins earlier letters written by Cornell to fellow artist Charles Henri Ford from 1938 to 1957.