Martin Luther's posting of the 95 Theses to the door of the Castle Church in Wittenberg on 31 October 1517 is one of the most famous events of Western history. It inaugurated the Protestant Reformation, and has for centuries been a powerful and enduring symbol of religious freedom of conscience, and of righteous protest against the abuse of power. But did it actually really happen? In this engagingly-written, wide-ranging and insightful work of cultural history, leading Reformation historian Peter Marshall reviews the available evidence, and concludes that, very probably, it did not.