Sobre la tirania

On Tyranny: Twenty Lessons from the Twentieth Century is a 2017 book by Timothy Snyder, a historian of 20th-century Europe. The book was published by Tim Duggan Books in hardcover and by Penguin Random House in paperback. A graphic version, illustrated by Nora Krug, was released October 5, 2021. The book topped the New York Times bestseller list for paperback nonfiction in 2017 and remained on bestseller lists as late as 2021. As of July 2025, over 1.4 million copies of On Tyranny have been sold and the book is on its 47th printing. On Tyranny focuses on the concept of tyranny in the context of the modern United States politics, analyzing what Snyder calls "America's turn towards authoritarianism." Explaining that "history does not repeat, but it does instruct," he analyzes 20th century Europe to identify conditions that can enable established democracies to transform into dictatorships. The 126-page-book is presented as a series of instructions on combating the rise of tyranny—such as "defend institutions," "remember professional ethics," and "believe in truth."