Early in its development, the subject matter of any field of surgery is too ill-defined and opinions are too fluid for the production of a book on the subject to be possible. Late in its development, controversy is at an end, and although it is still possible to produce a textbook, it is too late to produce a book that might stimulate discussion and crystallise ideas. This book has that objective, it being the Editor's view that the field of the surgical treatment of arthritis of the knee had reached an appropriate intermediate stage in 1978 when this text was written. Three broad issues stand out as being in need of resolution before the optimum form of surgical treatment for a given knee can be defined more convincingly than is possible at present: Firstly: What symptomatic and physical features of the knee are to be recorded pre- and post-operatively, upon the basis of which comparisons can be made between the results obtained by two different surgeons or with two different tech­ niques. The resolution of this issue requires general agreement not only upon what features of the knee should be recorded but, crucially, upon how these features should subsequently be presented so as to characterise a particular group of knees.