Abstract Scholars of the European Middle Ages are well acquainted with bestiaries. These compendia of pithy stories about animal lore told in the service of catechetical instruction were especially popular in the twelfth and thirteenth centuries. Manuscripts of them survive in the dozens, many of them with lavish illustrations of the animals, plants, and fantastical beasts described therein. A recent exhibition of medieval bestiaries at Getty Museum in Los Angeles yielded a sumptuous catalogue (Book of Beasts: The Bestiary in the Medieval World, edited by Elizabeth Morrison and published in 2019) that provides an ideal starting point for anyone interested in this fascinating genre and its stunning illuminations. Underlying the success of the bestiary in the medieval Latin tradition is a modest Greek text from late antiquity: the Physiologus. Dating from the second or third century, this collection of forty-eight short and strange animal stories with Christian messages was probably composed in Alexandria. Untitled in the manuscript tradition, it takes its name from the anonymous natural scientist – Physiologus – whose authoritative voice narrates the text. As the volume under review makes clear, the Latin tradition was by far the most successful legacy of the Physiologus, but its reach and influence were surprisingly broad owing to the universal appeal of its charming contents, which is evident in the richness of the vernacular translations derived from the original Greek text.