A book of insight, reaction and analysis to commemorate the tenth anniversary of 9/11.A decade after that fateful autumn day, the extraordinary images and memories remain with us where we were when we heard the news; how we felt at seeing the first, then the second tower collapse. 9/11: Ten Years On brings together the very best Guardian journalism of the past ten years to offer a moment of reflection and understanding, with a new introduction by Ed Pilkington.