This is a practical guide to the optimal clinical use of pulmonary function tests. Its focus is on the clinical utility of the most common tests: what the test measures; what the results mean; what kinds of abnormalities the test can detect; and what kinds of clinical questions the test can answer. Coverage includes tests for measuring airway obstruction, response to bronchodilators, diffusing capacity of lungs, gas exchange, lung resistance and compliance, distribution of ventilation, and maximal respiratory pressures. Also included are chapters on preoperative pulmonary function testing and tests of exercise capacity. The authors discuss test patterns in various diseases, offer guidelines on when to test and what to order, and explain how to interpret test results. The concluding chapter presents illustrative cases.