Salles has been a familiar face in world cinema for a couple of decades now, but it was his 2004 film "The Motorcycle Diaries" that saw him become the obvious choice to helm "On the Road." As the director says, "we started to talk about this in 2004 after 'Motorcycle Diaries' premiered at Sundance, what became clear to me is that being passionate for the book for so many years, I discovered it at 18 and I fell in love with it immediately." But Salles wanted to truly immerse himself in the material, and had "the idea to do a documentary following the paths of the book, interviewing the characters of the book who were still alive...and the poets of this generation that then became the beat generation. We interviewed Gary Snyder and Michael McClure, Lawrence Ferlinghetti, Diane de Prima. We also interviewed artists who were influenced by Kerouac or by the beat generation in general, [people like] David Byrne. This took four to five years. The initial years were ones where we were in and out because I was also doing other things. But we were diving into this social political historical context to better grasp it. At one point it became so fascinating that I would have been completely satisfied if the quest had ended there."
Earlier versions of the script had been done by Francis Ford Coppola and Russell Banks, among others.
After "The Motorcycle Diaries," Salles was invited, through "Moonrise Kingdom" co-writer Roman Coppola, to go and see his father, Francis Ford Coppola, who'd held the rights for many years. A number of scripts had been in the works, even before Coppola was involved (including an early version which "ended up with the punishment of the Dean Moriarty character, [who] would die in a car," inspired by the recent death of James Dean). Coppola got involved in '79, and according to Salles "got back to the source, and the adaptations became much more truthful to the original text." Coppola also brought in other writers: "Barry Gifford ('Wild At Heart,' 'Lost Highway') wrote a beautiful adaptation, and Russell Banks ('The Sweet Hereafter') wrote an adaptation that actually started quite differently from the book because it was Kerouac at the end of his days who reminisces about his youth." But Salles went back to the newly released, unedited version of the book for his own take, and the script was written by 'Motorcycle Diaries' partner Jose Rivera.