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.

His journal page for February 1, 1961, is dominated by a color sketch of the painting The American Sweetheart, with a note to the left indicating to add names to the twenty circles in the work. Below the sketch, Indiana records that he had a visit from St & Barb (Stephen and Barbara Durkee), and that their reaction to his works The American Sweetheart and The Sweet Mystery was positive.