This book serves as a definitive guide to diagnosing shoulder conditions for all levels of orthopaedic surgeon with an interest in shoulder pathology, and for junior surgeons in training. It comes at a time when the knowledge regarding shoulder conditions has vastly improved, with the shoulder sub-speciality growing at a rapid pace in terms of practitioner numbers, procedures and evidence-base. However, with the multitude of special tests for shoulder conditions, the clinician faces  a variety of sensitivities and specificities of the respective tests. It is unclear, in most circumstances, which single test is the best and growing evidence confirms that a set of tests is superior for diagnosing shoulder conditions. This forms the basis of cluster testing, which is the key concept for the title and content of this book. In many common shoulder diagnoses the preference for clusters has been reflected in both experience and clinical evidence, but for conditions where evidence for clusters is less clear, a consensus-based approach is utilised by the authors of this key resource for diagnosing shoulder conditions.