After the Mass Ordinary, the Magnificat was the liturgical text most frequently set by Renaissance composers, and Orlando di Lasso's 101 polyphonic settings form the largest and most varied repertory of Magnificats in the history of European music. In the first detailed investigation of this repertory, David Crook focuses on the forty parody or imitation Magnificats, which Lasso based on motets, madrigals, and chansons written by such composers as Josquin and Rore. By examining these Magnificats in their social, historical, and liturgical contexts and in terms of composition theory, Crook opens a new window on the breadth and subtlety of an important composer often harshly judged on his use of preexistent music.Crook places Lasso amidst the Counter-Reformation reforms at the Bavarian court where he composed the Magnificats, and where there emerged a fanatical Marian cult that favored this genre. In a section on compositional procedure, Crook explains that Lasso abandoned the traditional eight psalm- tone melodies in his imitation Magnificats, considers the new ways he found to represent the tones, and describes how Lasso's experimentation reflected the complex relationship between mode and tone in Renaissance theory and practice. Arguing that Lasso's varied uses of preexistent music defy current definitions of parody technique, Crook, in his final chapter, reveals the imitation Magnificats as vastly more imaginative and innovative than previous characterizations suggest.