In this day of high-tech tests, the fourth edition still places a somewhat refreshing emphasis on conventional radiography. I believe this is important, as conventional radiography still constitutes about 80% of emergency radiology imaging studies. With that said, the book has done a very good job in keeping pace with the newer imaging modalities of CT scanning, MRI, and ultrasound. For readers of CHEST, I specifically concentrated on the 144-page chapter on thoracic radiology. This includes extensive discussions of traumatic and nontraumatic conditions, with excellent sections on inflammatory processes and congestive heart failure. There are excellent discussions on the diagnosis of pulmonary embolism, including the role of CT pulmonary angiography, aortic dissection (CT scanning and MRI), and acute traumatic aortic injury (CT scanning).