The enormous importance of the diseases of the locomotor system in all populations and the large component of general clinical practice which they represent have not, in the past, been matched by an appropriate pathological effort. Increasing expectation of an active and long life has resulted in a great increase in specialisation in Rheumatology and rehabilitation of those with crippling diseases. This volume presents many of the pathological advances that have followed this clini cal interest, beginning with reviews of changes in biological materials obtained by in vasive investigation of joints, continuing with an account of therapy Goint replace ment) and also describing a "new" hazard - hyperbaric injury. Experimental models of joint disease are also described as are other entities such as crystal deposition dis ease. A detailed consideration of the electron microscopy of bone tumours is included since this data is not widely available in current texts. Finally, the role of the HLA system in rheumatic disease is included, indicating the value of close co-operation between clinician and pathologist in defining and link ing the various rheumatic syndromes. London Contents Examination of Synovial Fluid. With 9 Figures P.A. Revell ........................................... . The Synovial Biopsy. With 20 Figures F. Eulderink. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25 Tissue Reactions to Joint Prostheses and the Products of Wear and Corrosion. With 20 Figures P.A. Revell. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 73 Bone and Joint Diseases in Workers Exposed to Hyperbaric Conditions."