Insurgence is designed to help business leaders apply new methods to the most important business problem they face in the world today: namely, how to overcome their incumbent mentality to maintain relevance and discover new sources of growth. At the convergence of lean, business model innovation, agile, and design thinking, insurgence is a methodology and business philosophy that will help leaders in incumbent businesses rediscover how to operate like small and nimble insurgents whilst maintaining many of their incumbent advantages. Incumbent businesses, often having enjoyed a long period of relative historical market stability, are increasingly unprepared for nimble insurgents coming on to the field of play and applying different assumptions and business models at speed and scale. These incumbent businesses find that the business models that fuelled their success are no longer robust to the change surrounding their business, and they are becoming increasingly obsolete, weighed down by a high degree of internal focus, inflexible internal controls, and an inability to innovate. Meanwhile, nimble insurgents strike at the heart of these weaknesses by formulating alternative core assumptions, building adaptive business models, and innovating in close proximity to customers and market needs. This book enables business leaders to characterise the difference between incumbents and insurgents, develop new ways of thinking about how to compete in this age of accelerating change, and provide a new framework for strategy and innovation that helps leaders to discover the essence of insurgence for their businesses. It uses rich case studies that illustrate both successful and unsuccessful efforts to help leaders move from theory to action at speed and at scale.