If forty traditions have been collected on a particular topic, what is such a book called?

A collection of traditions, especially in the context of folklore, anthropology, or cultural studies, is generally referred to as an "anthology." When specifically mentioning that it contains forty traditions, it may also be termed a "compilation" or "collection."

Anthologies are significant as they curate various viewpoints, stories, or traditions on a particular subject, providing a comprehensive understanding of the topic. They serve as valuable resources for researchers, students, and anyone interested in the cultural significance behind the traditions presented. In this context, a book featuring forty traditions may be aimed at illuminating a specific cultural heritage or thematic exploration, highlighting the diversity and richness of those traditions.