This famous text is much beloved by medical students and physicians-in-training throughout the English-speaking world, as its many editions indicate. Despite its relatively narrow focus, it is chock full of the pearls of clinical wisdom that students and practitioners treasure, and many of these lessons apply to medicine in general. The book was well characterized by a reviewer of an earlier edition for The New England Journal of Medicine: If only one book about surgery could be made available to physicians from all specialties, it should probably be Silen's recent revision of Cope's Early Diagnosis of the Acute Abdomen. Since the book first appeared more than 30 years ago, it has remained the classic treatise on the initial approach to abdominal pain. Because acute, severe abdominal pain is still a common problem whose misdiagnosis can result in quick death, each generation of beginning physicians is faced with the urgency of learning to make a diagnosis in this high anxiety situation and they appreciate the wise, humane, precisely detailed guidance offered by Cope and Silen. For the 21st Edition, Silen has again updated the text in a respectful but significant way. He has strengthened its emphasis on pitfalls in the interpretation of CT and ultrasound scans, on misadventures caused by over-reliance on blood tests and radiographs, and on careful history-taking to avoid the costs of inappropriate lab tests. He has also reviewed the data from a randomized clinical trial indicating that patients should receive adequate analgesia while awaiting a definitive diagnosis, a dictum that is contrary to traditional teaching.