For those unfamiliar with his work: Professor Folsom is a leading expert on Walt Whitman and his oeuvre, and is one of the cofounders of the Walt Whitman Archive, an essential resource. The Archive, and Folsom in particular, collaborated with IWP to create WhitmanWeb, which you can find at https://iwp.uiowa.edu/whitmanweb/en.
Folsom later published with Merrill an edition of SONG OF MYSELF that includes a complete commentary in which they "carry on a dialog with Whitman, and with each other, section by section, as they invite readers to enter into the conversation about how the poem develops, moves, improvises, and surprises." Folsom is also the founder of "Whitman Week," which first took place in 2008 at Dortmund.