This chapter demonstrates the influential role of printed books in defining Chaucer’s canon and the implications of that newly formed canon for older books. It considers a series of texts which early modern readers added to manuscripts (and some early printed books) to update and improve them: short poems including Prophecy, Words to Adam, and Bon counsail; Robert Henryson’s Testament of Cresseid; various Plowman-themed texts; the Tale of Gamelyn; and the Retraction. The chapter argues that print made available an array of genuine and apocryphal works which readers could extract, assemble, and reconfigure in line with their own tastes and understanding of the Chaucer canon. The evidence collected in the chapter shows the persistence of particular narratives about Chaucer’s works which were promoted in print: that he was a poet of fin amour, that he condemned Criseyde to a wretched death, that he assigned his Plowman an anticlerical tale, and that the Retraction was a later monkish forgery. The changeability of the manuscript books chronicled in this chapter reflects a concurrent reshaping of Chaucer’s reputation in the period and the variability of his literary canon itself.