The modern field of abdominal wall surgery relies on a thorough understanding of all components of the abdominal wall as well as their function and physiology. In the past decade, we have witnessed steady progress in the understanding of the abdominal wall itself, enabling creation of more complex procedures, including myofascial and musculocutaneous advancement flaps via component separation and muscle releases. A comprehensive grasp of technical options should occur in tandem with a complete and systematic understanding of abdominal wall anatomy. This chapter provides a framework for understanding the clinical anatomy of the abdominal wall as well as the relevant physiology and critical relationships that arise during surgery. The chapter is framed to emphasize fundamental principles of surface and deep anatomy as well as more subtle clinical findings based on these foundations that are pertinent to modern abdominal wall surgery.