Placental and perinatal pathology has evolved significantly in recent years. For many pathologists, examination of the placenta has been challenging for several reasons. It is an organ comprising tissue from two individuals and is ever-changing as it matures throughout gestation. It has only been in the last 50years or so that interest hasbeensparked in this important organ.Muchof this interest isdue to the extensive work of Kurt Benirschke and others like him who took on an organ that was often discarded and found that it provided a wealth of information on both the fetus and the mother. There has also been renewed interest from the legal profession as the placenta has taken a major role in adjudicating malpractice cases in obstetrics. Therefore, it is timely to present a text with practical coverage of the current concepts, diagnostic criteria, differential diagnoses, and pitfalls in the diagnosis of placental lesions. In this volume, we have attempted to bring together a group of the most knowledgeable pathologists in this area to cover a number of important topics in this field.