The folded bark books called pustaha are grimoires containing divination techniques, ritual practices, narratives, and methods of protecting one’s community from adversaries. The pustaha are composed by datu ritual specialists, who use them as repositories of esoteric knowledge and ritual instruction for passing down through generations of teacher-student relationships.

Only datu and traders move freely across the five Batak lands in the highland interior of contemporary North Sumatra, Indonesia, resulting in manuscripts incorporating variations in language and script from the different regions. Combined with the fact that the pustaha are written in hata poda, an ancient variant of the Batak language with many Malay loanwords known only by the datu, the contents become shrouded in secrecy outside the direct line of transmission.