This book discusses the considerable influence exerted by Isidore's Etymologiaeon upon the compilation of early medieval enigmata. Either in the form of thematic clusters or pairs, Isidorean encyclopedic patterns are observed not only in major Latin riddle collections in verse but can also be detected in the two vernacular assemblages contained in the Exeter Book. As with encyclopedias, the topic-centered arrangement of riddles was pursued by compilers as a strategy intended to optimize the didactic and instructional possibilities inherent in these texts and favor the reader' assimilation of their contents. This book thus provides a thoroughgoing investigation of medieval riddling, with special attention to the Exeter Book Riddles, demonstrating that this genre constituted an important part of the school curriculum of the early Middle Ages.