This monograph is the first comprehensive study of the monsters and monstrous beings in The Faerie Queene. It takes as its starting point Thomas Cooper's sixteenth-century definition of monstrum, which links the monstrous to the notion of the physically deformed, the violation of the rules of nature, and the idea of the sign that needs interpreting. These distinctions also represent Spenser's use of monsters and monstrous beings in The Faerie Queene: he fashions monstrosities as physical deformities violating the rules of nature in order to establish them as meaningful ciphers in an 'extended Allegory' designed to 'fashion a gentleman or noble person in vertuous and gentle discipline'. The book combines an inventory of Spenser's creatures with a study of the poem as a monstrous artifact. It first offers a taxonomic account of the monsters in The Faerie Queene, which analyses them along systematic and anatomical parameters. It then treats monsters and monstrous beings as signs interacting with the early modern discourse on the autonomous poet, who creates a secondary nature through the use of his transformative imagination and fashions monsters as ciphers that need to be interpreted by the reader. The book will appeal to Spenserians and scholars in Renaissance and monster studies, as well as to postgraduate students. It will also be of great interest for university libraries as a reference work on monsters and as a compendium to Renaissance literary criticism.