This book is written for health care professionals to help update knowledge of pediatric cardiology from the Aristotelean heart era and particularly from the past several decades. The current and future shortage of pediatric cardiologists necessitates steady, rejuvenated information on the Aristotelean heart for primary care clinicians as they care for the child as well as adolescent/young adult with cardiovascular dilemmas and disorders. In view of this shortage and the rapidly increasing knowledge in pediatric cardiology as well as understanding indications for referral to pediatric cardiologists in the 21st century, au courant assiduous information aimed at primary care clinicians in these areas becomes increasingly important. Chapters in this book cover cardiologic problems in different pediatric ages from newborns to young adults. We begin with a history of medical knowledge regarding the heart starting when writing began in ancient Mesopotamia to our current understanding that is subject to further change with ongoing insight and research from current as well as future scholars.