The song is a satirical and surrealistic story that jumbles together historical and literary and narrative references from the voyages of Columbus to the Mayflower to Moby Dick to the present day.
Historian Sean Wilentz described the song as "a six-and-a-half-minute roller-coaster ride, more joyful than scary" in which Dylan constructs a manic journey through American history: "a hipster sailor travels across a historical landscape where it’s sometimes 1620, sometimes 1851, sometimes 1492, but always 1965 as well—and could just as easily be America today, which is really the point."
Wilentz argues "115th Dream" shares "an identical melody" with "Motorpsycho Nitemare" and both songs revolve around a hapless traveling salesman who is constantly "getting in and out of jams".
He recorded what would become the final album version a day later, with Bobby Gregg on drums, Bill Lee on bass, and Paul Griffin on piano.
[6] The track commences with an early take of Dylan beginning to play the song alone before producer Tom Wilson is heard bursting into laughter[7] and signalling for a start-over.