Comprehensive Manuals in Pediatrics are designed to broaden the prac- titioner's clinical scope by providing a wide range of diagnostic and management skills ordinarily considered to be the exclusive domain of the specialists. Although the series as a whole constitutes a comprehensive text in pediatrics, each volume stands on its own as a self-contained reference for the busy practitioner. In order to maintain a uniform style and coverage of each subject, each manual is usually written by no more than one or two authors. Each author is an acknowledged expert in his or her field and provides a comprehensive, up-to-date account of the topic under discussion. Prac- tically oriented, each volume offers concise guidelines and courses of treatment. Michael Katz E. Richard Stiehm Preface The preface-my opportunity to rationalize this labor, titillate the reader, philosophize or otherwise self-indulge. I'll take full advantage. Why write a book? After fifteen years' experience as an infectious disease consultant, teacher and researcher, I feel it is time to speak out! I have spent the majority of my waking hours thinking, reading and writing about childrens' infectious disease problems, have amassed a veritable Fort Knox of publications on the subject and have been reasonably out- spoken. Yet the field continues to progress with reckless speed and the gaps between our knowledge and effective communication of new infor- mation remain wide. I am eager to accept more responsibility for teaching yet my audience has been limited.