As has been well documented, the printed word was an essential vehicle for the transmission of reformed theology, and one that has left a tangible record for historians to explore. Yet as contemporaries well recognized, books were only a part of the process. It was the spoken word – and especially preaching – that created the demand for printed works. Sermons were the plough that prepared the ground for Lutheran literature to flourish. In order to better understand the relationship between oral sermons and the spread of protestant ideas, Preaching and Inquisition in Renaissance Italy draws upon the records of the Roman Inquisition to see how that institution confronted the challenges of reform on the Italian peninsula in the sixteenth century. At the heart of its subject matter is the increasingly sophisticated rhetorical skill of heterodox preachers at the time, who achieved their ends by silence and omission rather than positive affirmations of Lutheran tenets.