The First Aid series for the USMLE preparation is a valuable study tool for anybody wanting to score well on the USMLE exams.  The 2011 edition of the First Aid for the USMLE Step I contains high yield subjects including embryology, microbiology, cardiovascular, musculoskeletal, respiratory, renal, gastrointestinal, neurology, and much much more.  This book also contains some practice material on the type of questions you may encounter during your exam.  In addition, there is a whole section dedicated to high yield images.  Common images in radiology.  This book is a must have.