The 20th century Spanish poet and philosopher Miguel de Unamuno contemplates his health in the following passage1–: Although he refers to his struggle with death and immortality, this passage reflects the process whereby physicians attempt to discern the significance of three-dimensional thoracic structures displayed as radiographic shadows on a flat viewing screen. The practice of intensive care medicine requires precise interpretation of portable chest radiographic images, and this activity has been referred to as an extension of the bedside physical examination. From a radiographic image, the appearance and function of various thoracic structures may be inferred through serial examinations. For example, in a patient receiving mechanical ventilation, radiographic findings of a pneumothorax such as an inverted diaphragm are indicative of increased intrathoracic pressure with potentially dire consequences. In ventilator-supported patients, daily chest radiographs are obtained to confirm proper placement of tracheal tubes, intravascular catheters, and thoracostomy tubes, as well as for early detection of barotrauma, pneumonia, or atelectasis. In fact, portable chest radiography accounts for a large proportion of radiographic examinations within many US hospitals, and the majority of these are performed in ICUs. Furthermore, various investigators have reported a benefit from performing daily chest radiograph examinations in patients in unstable condition receiving mechanical ventilation.2–3 Accordingly, there is much useful information to be obtained from close examination of serial chest radiographs, and daily viewing has become an essential component of intensive care medicine.