Kerouac often promoted the story about how in April 1951 he wrote the novel in three weeks, typing continuously onto a 120-foot roll of teletype paper. Although the story is true per se, the book was in fact the result of a long and arduous creative process. Kerouac carried small notebooks, in which much of the text was written as the eventful span of road trips unfurled. He started working on the first of several versions of the novel as early as 1948, based on experiences during his first long road trip in 1947. However, he remained dissatisfied with the novel. Inspired by a thousand-word rambling letter from his friend Neal Cassady, Kerouac in 1950 outlined the "Essentials of Spontaneous Prose" and decided to tell the story of his years on the road with Cassady as if writing a letter to a friend in a form that reflected the improvisational fluidity of jazz.