Timothy Snyder, author of great works on Europe between Hitler and Stalin and on the Holocaust, warns us: we are not safe from the bloody totalitarianisms of the twentieth century. But we have an advantage, we can learn from history. And from our recent past. For this Snyder has drawn twenty lessons to avoid repeating today, between nationalisms and populisms, the mistakes of a tragic era, that Era of Tyrants of which Nora Krug gives us the echo, mixing her illustrations with photos and splinters of a time we wish would never happen again. Because if conforming to injustice is easy, resisting is a choice of courage without which freedom dies.