This deep and incisive study explores 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 of learning to adapt to various new weapon systems, theories and strategies. This culminates with a bracing look at Putin’s disastrous invasion of Ukraine, yet another case study in the tragic results when leaders refuse to learn from history, and an assessment of the nature of future warfare. Filled with sharp insight and the wisdom of experience, this is not only a critical assessment of our recent past, but also an essential primer of modern warfare that provides crucial knowledge for waging battle today as well as for understanding what the decades ahead will bring.