The legend of Phra Malai, a Buddhist monk of the Theravada tradition said to have attained supernatural powers through his accumulated merit and meditation, is the main text in this 19th-century Thai samut khoi (folding book) held in the Thai, Lao, and Cambodian Collections of the British Library. Phra Malai figures prominently in Thai art, religious treatises, and rituals associated with the afterlife, and the story is one of the most popular subjects of 19th-century illustrated Thai manuscripts. The earliest surviving examples of Phra Malai manuscripts date back to the late 18th century, although it is assumed that the story is much older, being based on a Pali text. The legend also has some parallels with the Ksitigarbha Sutra. The Thai text in this manuscript is combined with extracts in Pali from the Abhidhammapitaka, Vinayapitaka, Suttantapitaka, Sahassanaya, and illustrations from the Thotsachat (Last ten birth tales of the Buddha). Altogether, the manuscript has 95 folios with illustrations on 17 folios. It was very common to combine these or similar texts in one manuscript, with Phra Malai forming the main part. These texts are written in Khom script, a variant of Khmer script often used in Central Thai religious manuscripts. Although Khom script, which was regarded as sacred, was normally used for texts in Pali, in the Thai manuscript tradition the story of Phra Malai is always presented in Thai. Because Khmer script was not designed for a tonal language such as Thai, tone markers and certain vowels that do not exist in Khmer script have been adopted in Khom script to support the proper Thai pronunciation and intonation.