In early modern Italy, protest, dissent and activism almost inevitably took the form of religious deviation. Heresy, rebellion, prophecy, and reform were not separate phenomena, but different expressions of the same underlying tension: the struggle between authority and conscience. This book traces this long and fragmented history through a series of individual lives, episodes, contexts, and experiences. From itinerant friars to persecuted humanists, from dissident noblewomen to prophetic women and accused witches, from physicians and scientists whose activities exposed them to suspicion to jurists who transformed law from an instrument of discipline into a language of freedom, and from rebellious communities to radical heresies: this volume explores how religion functioned both as a tool of repression and as the most powerful medium of resistance. Accusations of heresy served to neutralize social conflict, delegitimize political opposition, and enforce obedience; yet the same label also opened spaces in which men and women could articulate demands for justice, autonomy, and dignity. Rather than offering a systematic theory, this volume presents a narrative reflection grounded in documentary traces, trials, banned books, sermons, and silenced voices. Its protagonists are not idealized heroes but often contradictory and fragile figures, whose gestures of non-conformity reveal the deep roots of freedom of conscience in Italian and European history. Moving from the age of the Counter-Reformation and the Inquisition to the threshold of political modernity, the book shows how dissent survives defeat by changing form-circulating underground, re-emerging in new languages, and reminding us that freedom is never granted, but continuously negotiated.