Hip pathology and nonarthritic hip conditions have only recently been recognized as a cause of hip pain. In 2003, Ganz, Leunig and colleagues described the concept of femoroacetabular impingement (FAI) as a cause of hip pain and a mechanism for end-stage hip osteoarthritis.  Ganz et al. also postulated that 70-90% of hip osteoarthritis is likely due to abnormal hip mechanics related to FAI, dysplasia, or other hip deformities. Over the past ten years, the treatment of these non-arthritic hip pathologies has grown dramatically, and has been estimated to grow by 15% each year. It is the largest segment of grown in sports medicine and orthopedics as a whole. However, no definitive reference yet exists on hip arthroscopy and hip joint preservation surgery. While books have been published on hip arthroscopy, these texts are limited to the technical aspects of the procedure and do not explore content related to hip joint preservation surgery. The scope of this book covers the basic science of hip pathology, anatomy, biomechanics, pathology, and treatment.  It has put together up-to-date research and has invited opinion leaders in the field to contribute to the text. The book is focused on disease pathology and provides comprehensive information on each disease topic, which is followed by technique-driven chapters to provide surgeons a reference for any procedure related to non-arthritic conditions of the hip.