Back pain is the commonest form of rheumatism and it is estimated to affect between 65% and 80% of populations sampled. The costs of back pain-related medical care and disability compensation make it one of society''s most significant non-lethal medical conditions. Whilst mortality is low, its morbidity is high, inconvenience great, and economic burden massive. The actual symptom of back pain is one of the commonest and most perplexing encountered in medical practice. A proper understanding of what it means is crucial for further medical advance. However, the field of back pain research probably has more experts than any other. Anybody who has back pain will, as often as not, expound views on all matters concerning causation and expectations. Indeed, it is not for a lack of ideas that this field of investigation has failed to make progress. A respected senior investigator advised me early on that patients could not even tell which side their pain was on. It was only many years later that I discovered why. Though the initial incident or accident would seem important to the patient and to the researcher, it is remarkable how little it helps distinguish patterns of back pain. Tests of inappropriate behaviour in the past have been widely disseminated and yet even the originators have said that they cannot be sure of the implications of positive non-organic test findings. This book will show that these ''indicators'' are not what they seem to be. In many cases, it is difficult to tell which level in the lumbar spine the pain comes from, and thus treatments such as injections or operation, may be given at the wrong level, let alone the wrong side. Though the various forms of back pain treatment seem to help some patients, when these same treatments are subjected to randomised controlled trials, the evidence for efficacy seems to all but vanish. With all these difficulties and uncertainties, it can be seen why low back pain presents one of the most fallible fields of healthcare. This book indicates that there are ways of dealing with the majority of these problems. Many of the answers from the research conducted were most unexpected. The reader is also advised that the scientific approach cannot deliver hard and fast answers to all contemporary questions in such a wide field and much has depended on the choice of problems to study. Whilst the tests used to distinguish the patterns in this study have their limitations, and whilst there is, as yet, only limited evidence as to the underlying pathology for the patterns recognised, it is felt that some of the other patterns identified are descriptive of diagnoses that are generally accepted. If the answers that are put forward appear to change the direction of understanding, it is hoped that you, the reader, will be able to carry the enquiry further when you see patients, advise treatment or even experience back pain yourself!