This is the 19th in a series of chronologies of international and domestic terrorist attacks and global, regional, and individual government and private responses. The year 2020 was sufficiently different from preceding years in this series that it merits separate treatment in the Introduction and has a separate chronology. This book uses the same definition of terrorism as found in its predecessors, allowing comparability across decades. Terrorism is the use or threat of use of violence by any individual or group for political purposes. The Introduction chapter provides an overview of terrorism developments in 2019 and 2020. The rest of the book includes a region-by-region (and within each, a country-by-country) look at terrorist incidents in chronological order-including a separate section updating events that occurred prior to 2019-and a bibliography. The author, Edward Mickolus, wrote the first doctoral dissertation on international terrorism while earning an M.A., M.Phil, and Ph.D. from Yale University. He then served in analytical, operational, management, and staff positions in the Central Intelligence Agency for 33 years, where he was CIA's first full-time analyst on international terrorism; analyzed African political, economic, social, military, and leadership issues; wrote political-psychological assessments of world leaders; and managed collection, counterintelligence, and covert action programs against terrorists, drug traffickers, weapons proliferators, and hostile espionage services. He founded Vinyard Software, Inc., (vinyardsoftware.com) whose International Terrorism Data Center provides the best publicly-available data on terrorists and events around the world.