Book excerpt: Abstract: A text for science professionals, prepared by a physician who has specialized in scientific communication, presents practical guidelines for conveying abstruse, difficult, or highly technical information to nontechnical audiences. The text sets out the basic principles of communication and illustrates these principles from the author's personal experiences. The material is organized into 2 principal parts: the first deals with presenting science through the mass media; the second considers presenting science directly to the public. General principles for communicating science to the public also are discussed. (wz).