"The purpose of the Pocket Companion is not intended to be a substitute for the full text, but rather to serve as an all-day companion, which distills the huge amounts of information from the parent text into small, digestible core concepts designed for rapid comprehension. The product is small enough to be carried in a coat pocket, and is great for looking up quick facts. It is intended primarily for medical students, although residents and other health professional students may use it. * Follows the primary text by incorporating all of the new science that is in the Textbook of Medical Physiology 12e. * Carry the same authoritative, useful knowledge that readers of Guyton have come to trust - right in your pocket * Easily locate more in-depth discussions inside the parent text with abundant cross-references and a parallel chapter organization" - from Amzon