Robert Indiana kept a series of illustrated journals during the late 1950s and 1960s, in which he discusses the development of his work as well as his daily life on Coenties Slip.

This journal page covers July 17–18, 1959, and July 18, 1960. In his short entry for July 17, 1959, Indiana mentions dining at Camillos with John (his partner, fashion designer John Kloss), and records "The Muses."

Indiana's entry for July 18, 1959, includes a sketch of an 8 x 4-foot painting with a note "add cartoon for." A note to the right of the sketch, added at a later date, states that the work became The American Sweetheart. Indiana also discusses a poorly planned trip to Staten Island, which included a long walk through the hills and fields of the island, picking berries on the way. He located the Tibetan museum, which was closed, but was unable to find the lighthouse or Frank Lloyd Wright's pre-fab. He records that "the beauty of Staten Island would probably soon be spoiled by the [Verrazzano] bridge, but as it is now it is tempting. Very country."

His entry for July 18, 1960, consists only of the comment "Visit Newman's," referencing a visit to the artist Barnett Newman's studio.