AFTER the appearance of the sixth edition, Herbert French had resolved to take no active part in any future production. I decided that it was not only desirable but necessary to undertake considerable reconstruction in the next edition. Although the basic principles of diagnosis must be static for all time, the considerably increasedscope of investigation by accessory aids demanded the inclusion of much new material and in many instances the production of entirely re-written rather than revised articles, especially as many of the earlier contributors have died or retired. By a more logical division and allocation among new contributors, considerable overlapping or repetition evident in earlier editions has been avoided and has resulted, it is hoped, in a more compact and generally useful work. It will be noticed that the title has been altered to conform to the actual contents. By judicious pruning the index has been simplified and abbreviated whilst retaining all essential references. This has been carried out by the publishers, Messrs. John Wright & Sons, of Bristol, with an accuracy ensured from their wide experience. The highest standard of format and printing confidently expected has been maintained. For many of the illustrations I am indebted to Professor J. Whillis, who is in charge of the Department of Medical Illustration, Guy's Hospital, and to Dr. T. H. Hills, Director of the Department of Diagnostic Radiology, Guy's Hospital. In other cases acknowledgment of the source is appended to the picture. To the deletion of obsolete material and the inclusion of much that is new must be added the editorial complication of extensive cross-references when several independent contributors have to be correlated—a difficulty enhanced by the long interval that has been unavoidable between the submitting of manuscripts and publication. I have been exceptionally fortunate in having as counsellor, collaborator, and contributor Sir Adolphe Abrahams. He has spared no pains in respect of writing, proof-reading, and general advice to help me to carry on the work of my old teacher. To him I offer my warmest thanks