Helpful links for today’s “Commonplace Book” Gary Gallagher explains why Gettysburg was not as important in 1864 as it is now. Norman Housley, “Saladin’s Triumph: The Battle of Hattin, 1187” Eliot A. Cohen and John Gooch, Military Misfortunes: The Anatomy of Failure in War (1991) “Visiting Chernobyl 32 Years After the Disaster” (The Atlantic, April 26, 2018)