The evolution of hernia surgery has led to the popularization of a variety of reconstructive techniques. The traditional approach described by Ramirez involves the creation of large skin flaps and associated significant wound morbidity. Minimally invasive modifications are known to reduce skin flaps and wound complications but limit mesh placement to intraperitoneal underlay in the vast majority of cases. Classic Rives-Stoppa retrorectus repairs provide durable outcomes with low morbidity but allow only limited medial myofascial advancement and insufficient sublay space for sufficient overlap of the visceral sac in many hernias. To address the shortfalls of the traditional retromuscular repairs, posterior component separation using transversus abdominis muscle release (TAR) was described. This modification allows for significant myofascial cutaneous advancement, wide lateral dissection, preservation of the neurovascular supply of the rectus abdominis muscle and provides a large space for mesh sublay. Most importantly, TAR allows for medialization of the abdominal wall components without raising lipocutaneous flaps. This chapter will describe the history of TAR, its anatomic and physiologic basis, indications/limitations, detailed technical considerations as well as a variety of clinical outcomes.