It is only recently that the orthopaedic world has begun to turn its attention to traumatic pathology of the posterior cruciate ligament. This ligament is the most important of the knee in terms of dimensions and mechanical properties, however, has been historically considered of insufficient clinical and surgical importance. Various factors have contributed to such an erroneous evaluation, such as: insufficient knowledge of joint biomechanics, lower traumatic incidence, and generally unsatisfactory results of its surgical treatment. Scientific literature in recent years has become enriched by new knowledge, especially in the anatomical and biomechanical fields, which have changed many of the past convictions. The authors have intentionally presented a panoramic view, as extensive and current as possible, pertaining to the pathology of the posterior cruciate ligament and have included important experts in the field in this published work. They have been asked to trace an agile educational path with the aim to guide the reader with a complete understanding of the topic. Particular attention has been dedicated to new knowledge of anatomy and biomechanics, in that they constitute the necessary foundations of medical science that are often neglected, especially in post-operative evaluation and rehabilitation. Surgical methodology has been described in every detail by each author, highlighting their advantages and risks, with the goal to supply the reader with a complete vision of the various techniques currently available in ligament reconstruction. Particular acknowledgement goes to the Publisher for his sensitivity to our requests, and for extensive freedom in the iconography that renders the text immediate and easy to understand.The authors are aware that future advancements in the subject presented will render some chapters in this work obsolete, but hope that the topics discussed can be of reference to clinicians and a stimulus for researchers interested in this work that J. S. Torg defined only a few years ago as "the last mystery of the knee".