If one acknowledges its limitations,<i>The Merck Manual</i>can provide an interesting reading experience. Certainly, few medical volumes contain so much information, so concisely stated, and at such a modest price. A distinguished editorial board conveys authority for what is said.<i>The Manual</i>probably comes as close as any available text in describing what is accepted medical practice in the United States today. Newer ideas receive mention, but the bulk of the text deals with long-established principles of diagnosis and therapy. The<i>Manual's</i>limitations are inherent in its design: brevity necessitates arbitrary statements, with opposing views given little or no discussion. References are almost nonexistent. Less common problems are listed, but not discussed. The scant pathophysiological information that is included does not encourage the student to "think through" the problems being considered. As a consequence, the<i>Manual</i>can be recommended as a review for students, residents, and practicing physicians, but