Ten years in the making and a masterpiece of reportage, “Columbine” is an award-winning journalist’s definitive account of one of the most shocking massacres in American history. It is driven by two questions: what drove these killers, and what did they do to this town? On April 20, 1999, two boys left an indelible stamp on the American psyche. Their goal was simple: to blow up their school, Ok...