Hugh D. Auchincloss III (Yusha) was Jacqueline Bouvier Kennedy Onassis' step-brother. After his father married Janet Lee Bouvier in June 1942, Yusha, age 14, and Jackie, age 12, spent summers together at Hammersmith Farm in Newport, Rhode Island, and corresponded extensively until her death in 1994.
Personal papers (1942-1997) consist of correspondence and a brief memoir. Much of the correspondence between Auchincloss and Onassis covers 1944 to 1952, as Onassis attended boarding school at Miss Porter's in Farmington, Connecticut and studied at Vassar College and the Sorbonne. In 1998, Auchincloss published of short piece on his childhood with Jackie entitled Growing up with Jackie: My Memories 1941 - 1953.