Agile Implementation describes the underlying theories and frameworks that explain health delivery systems and lays out the 8 steps of the Agile Implementation Model founded by Malaz Boustani, MD, MPH and Jose Azar, MD. In today's complex healthcare environment, implementing evidence-based care into real-world practices is difficult and time consuming. Even methods that are known to be effective allow for limited flexibility and therefore fail as often as they succeed. Through much study and experimentation, Malaz Boustani, MD, MPH, Jose Azar, MD, and Craig A. Solid, PhD have come to understand how individuals' interactions within the complex social systems of hospitals, clinics, and other care delivery organizations shape the decisions and behaviors of those involved. Upon this foundation and through leveraging theories of behavioral economics, we have developed the Agile Implementation Model, a process for selecting, adapting, implementing, evaluating, sustaining, and scaling evidence-based healthcare interventions. This model acknowledges the uniqueness of each individual facility and considers individuals within the system to be semiautonomous but interconnected. In tandem with illustrative examples, Agile Implementation describes the underlying theories and frameworks that explain health delivery systems and lays out the 8 steps of the Agile Implementation Model. Upon completing Agile Implementation, readers have a better understanding of why certain quality initiatives succeed while others fail and have tangible, actionable tools for implementing effective and sustainable change in the healthcare setting.