This chapter examines Kerouac’s Buddhism and is informed by archival research of his unpublished Buddhist writing, which in provides a more complete understanding of Kerouac’s Buddhism than what can be learned from his published works. A detailed analysis of his published and unpublished writing reveals that Kerouac’s Buddhist period should be separated into an Early Buddhist Period (1953–58) and a Later Buddhist Period (1959–mid-1960s). Kerouac’s Early Buddhist Period is one of intense study and practice. And while his enthusiasm for the religion certainly decreased from 1959 to his death in 1969, it is inaccurate to state that he did not study Buddhism after 1958, as revealed by his unpublished diaries. Thus, 1959 through to 1967 should be identified as his Later Buddhist Period during which he continued his textual study, occasional meditation practice, and reworking of Buddhist texts. Additionally, this chapter argues that Kerouac believed himself to be a transmitter of Buddhism for Americans and that the Buddhism he believed helped his own suffering – and was, by extension, most useful for American practitioners – was largely rooted in the Diamond Sūtra (Vajracchedikā Prajñāpāramitā Sūtra) and in key Mahāyāna ideas.