The curriculum that evolved into the ideas for this series was inspired by two talented and forthright students, Philbert Yau and Chuck Rosipal, who have since graduated from medical school. It has been a pleasure to work with Dr. Barry Simon, a wonderfully skilled and compassionate emergency room physician, and Dr. Kay Takenaka, who is as talented in her writing and teaching as she is in her clinical care. It has been excellent to have Adam Rosh join us. McGraw-Hill and I have had the fortune to work with Adam while he was a medical student, resident, and now an accomplished emergency medicine physician and educator. Likewise, I have cherished working together with my friend since medical school, Terry Liu, who initially suggested the idea of this book. I am so proud of my daughter Allison who has become an accomplished nurse, and also an expert in the "case files" format. This fourth edition has five new cases, includes updates on nearly every case, and is completely reorganized so that the cases fit into condition-based systems. I am greatly indebted to Catherine Johnson, whose exuberance, experience, and vision helped to shape this series. I appreciate McGraw-Hill's believing in the concept of teaching through clinical cases. I am also grateful to Catherine Saggese for her excellent production expertise and to Cindy Yoo for her wonderful editing and outstanding production skills. Without the support of Dr. Patricia Butler in the Office for Educational Programs, Dr. Sean Blackwell, Chair of the Department of Ob/Gyn, and Dr. John Riggs, Ob/Gyn Chief at LBJ Hospital, I would not have been able to succeed in this book. Most of all, I appreciate my everloving wife Terri, and four wonderful children, Andy and his wife Anna, Michael, Allison, and Christina, for their patience, encouragement, and understanding.