In CT Suite the doctor and anthropologist Barry F. Saunders provides an ethnographic account of how a particular diagnostic technology, the computed tomographic (CT) scanner, shapes social relations and intellectual activities in and beyond the CT suite, the unit within the diagnostic radiology department of a large teaching hospital where CT images are made and interpreted. Focusing on how expertise is performed and how CT images are made into diagnostic evidence, he concentrates not on the function of CT images for patients but on the function of the images for medical professionals going about their routines. Yet Saunders offers more than insider ethnography. He links diagnostic work to practices and conventions from outside medicine and from earlier historical moments. In dialogue with science and technology studies, he makes a significant contribution to scholarship on the visual cultures of medicine.