The editor states that the aim of the Current Concepts in Radiology series is bring together selected aspects considered important to the practicing radiologist and radiologist in training for optimal application of current information to patient care. This second volume of the series is concerned with three areas in particular: (a) study of more effective and efficient uses of radiology, (b) understanding of the radiographic image and the effect of its characteristics on radiological interpretation, and (c) recent advances in four specific topical areas. In the first four chapters, new methods of evaluating various aspects of efficient and effective uses of radiology are presented and systems analysis is used to study the operation and management of radiology departments. Study of the usefulness of radiological information by means of systems modeling is covered well by Dr. Potchen, whose concept of the use of radiology by clinicians in defensive medicine to protect themselves from future medicolegal action is nicely encapsulated and documented. Decision analysis and a method of measuring the usefulness of radiological information to clinicians, based on Baye's Theorem, are given in Chapters 3 and 4. Three chapters cover the radiographic image and its interpretation, specifically (a) electronic imaging techniques, (b) receiver operating characteristic (ROC)analysis, and (c) optimization of chest radiography techniques. The chapter by Dr. Lusted on ROC analysis in terms of decision theory in signal detection is a good example of an expert translating concepts from one discipline (decision theory) to another (radiological diagnosis) so that they may be applied to the study of observer performance. The specific areas of updating information covered in the final four chapters include (a) special procedures in pulmonary radiology, (b) radiological diagnosis of asbestos-related disease in the pulmonary and gastrointestinal systems, (c) recent advances in radiology of the gastrointestinal tract (including pharmacological angiography), and (eI) the 'use of nuclear medicine procedures in emergency situations. As the editor points out, preparation of this volume was completed prior to the recent rapid development and expansion of the clinical use of computed tomography and ultrasound, and the prodigious developments in these two areas make a good portion of the nuclear medicine section obsolete. Nevertheless, this volume is highly recommended for those radiologists who have an urge to delve into more basic concepts of radiological diagnosis and the consequences of image interpretation. For those who are looking strictly for diagnostic pearls in specific problems, this volume is not an in-depth presentation of the newest and best radiological signs, nor was it intended to be.