The Correspondence contains almost 40,000 letters, with the earliest letter dated from 1904. The bulk of the correspondence dates from the 1930s until Olgivanna Lloyd Wright's death in 1985. The correspondence is physically arranged alphabetcially by correspondent. For every letter, the inventory includes a brief note describing the contents of that letter. Olgivanna Lloyd Wright is the writer of about 7,000+ letters in the collection (marked as "Sender" in the inventory); the remainder of the correspondence was sent to her by (marked as "Receiver" in the inventory).