In previous books, Holocaust historian Timothy Snyder dissected the events and values that enabled the rise of Hitler and Stalin and the execution of their catastrophic policies. With Twenty Lessons, Snyder draws from the darkest hours of the twentieth century to provide hope for the twenty-first. As he writes, "Americans are no wiser than the Europeans who saw democracy yield to fascism, Nazism and communism. Our one advantage is that we might learn from their experience."