The Guyton and Hall Physiology Review, by Dr. John E. Hall, is an ideal way to prepare for the USMLE Step I. More than 1,000 board-style questions, as many as 30 percent revised for this edition, test your knowledge of the most essential, need-to-know concepts in physiology. Review the physiology of all major body systems, with emphasis on system interaction, homeostasis, and pathophysiology, and master a large amount of information in an abbreviated time.