This book is a call to action. It is no longer sufficient for an organization to simply be effective. Today's organizations must also develop agility in order to successfully cope with the complex challenges they face in a dynamic and uncertain world. This book explains why agility, once a nice-to-have capability, is now an imperative. Readers are provided with an in-depth understanding of this essential capability, its enablers and inhibiters, and ways to visualize and measure agility. Experimental results are used to illustrate the agility advantage as well as the adverse consequences of a lack of agility. This book outlines a plan to improve an organization's agility, and identifies the research needed to improve our understanding of agility.