The 'randomized clinical trial' is the process whereby a selection of patients, chosen purely at random, are tested either for the presence of a disease, or for the examination of the effects of new drugs or therapies. In this book, the author makes a plea for wider use of randomized clinical trials when introducing any new therapy. He cites many examples of how careful trials can overturn preconceived or ill-conceived notions of a therapy's effectiveness and how trials can lead to a clearer comprehension of clinical anomalies. The author gives careful guidance on how to avoid pitfalls and much useful information on how trials can be set up. His own expertise comes from tackling the problems of certain visual defects in the new-born. From reviews of the hardback edition: 'A clear well written exposition of the problems that face a clinical investigator and of the possible ways of solving them...The compelling quality of Silverman's book is his philosophical attitude that gives it life' British Medical Journal 'An engaging and well written account of an important part of modern medical research.' Lancet