For the 20th edition of this classic text, Silen has expanded his discussion of the role of CT scans in diagnosing abdominal pain and cut the material on such obsolete procedures or nosologic entities as abdominal paracentesis, pyplyositis and Bornholm's disease. This edition aims to reaffirm the text's reputation as an outstanding guide to the difficult task of diagnosing and deciding how to manage acute abdominal pain, where decisions must be made quickly and mistakes can kill patients. More generally, it aims to provide a venerable text on the art and science of bedside diagnosis.