Most subjects in clinical physiology are difficult to understand. In a day and age where the multi-tasking health provider's time is precious and attention span short, it is necessary to retain focus on the aspects of clinical medicine which truly matter; at the same time it is more rewarding to build up difficult concepts in a stepwise manner. Medium sized handbooks are increasingly becoming popular. The purpose of this book is to acquaint the reader with blood gas/acid-base interpretation. There is a strong thread of pulmonary and renal physiology running through the text; an attempt has been made to simplify concepts and explain the whys and hows in health and disease. The book is almost exclusively set out in the form of flow-diagrams/algorithms. The treatment of the subject in this format, describing processes in logical steps should make it easy for the reader to cover a difficult-and sometimes dreaded- subject rapidly.