“On Tyranny: Twenty Lessons from the Twentieth Century,” by Timothy Snyder. New York: Tim Duggan Books, 2017. ISBN: 978-0-8041-9011-4. 128 p. $7.99 (e-book, ISBN: 978-0-8041-9012-1. $3.99) Historian Timothy Snyder’s latest book, “On Tyranny: Twenty Lessons from the Twentieth Century,” is a short pocket-sized book of 127 pages broken down into 20 chapters. Chapters headings are:...