The world of science as it relates to health has moved rapidly since the publication of the first edition of The Encyclopedia of Common Diseases. In the 60 s alone, hearts were transplanted, the Pill passed into common usage, scores of environmental causes of" cancer were identified, nutritional therapy for emotional distur- bances earned new respect and hundreds of other changes in our attitudes toward disease became com- monplace. In terms of health, the years since World War II have broug-ht--C~civilized world into a whole new era. The rapidity has developed with which this-C , explains why the ew era in medicine material in this edi- tion is more than 75 percent new. o$.~age-)ubjects, such as crib death and venereal disease, di~{ not appear in the original at all. Others, such as t~motional and Nervous Disorders and Back Ailmen/{s, have been greatly expanded. Some sections, 4aa4ticularly those on the heart and cancer, are books in themselves. Each disease section has been carefully researched tbr the latest intbrmation and all medical and sciei~- tific conclusions are based on reports from the most respected of the world s medical and scientific jour- nals.