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.

In his journal page for May 7, 1961, Indiana records going to bed at 6 a.m. after a "late, late, late show and an unusually prolonged game of Monopoly," which he won. He notes that it was a grey, wet day, and that he repainted the black on the The Sweet Mystery, which is illustrated by a small sketch on the page. He also mentions varnishing a couple of paintings and stretching a new canvas.