All of the essential information you need from the world's foremost medical physiology textbook - right in your pocket! Pocket Companion to Guyton and Hall Textbook of Medical Physiology, 13th Edition, reflects the structure and content of the larger text, helping you recall and easily review the most essential, need-to-know concepts in physiology. - Important information can be grasped quickly, thanks to concise, readable text carefully crafted to make physiology easier to understand.