In this deep and incisive study, General David Petraeus, who commanded the US-led coalitions in both Iraq, during the Surge, and Afghanistan and former CIA director, and the prize-winning historian Andrew Roberts, explore over 70 years of conflict, drawing significant lessons and insights from their fresh analysis of the past. Drawing on their different perspectives and areas of expertise, Petraeus and Roberts show how often critical mistakes have been repeated time and again, and the challenge, for statesmen and generals alike, of learning to adapt to various new weapon systems, theories and strategies.