Welcome to the 21st Edition of Nelson Textbook of Pediatrics – the reference of choice among pediatricians, pediatric residents, and others involved in the care of young patients. This fully revised edition continues to provide the breadth and depth of knowledge you expect from Nelson, while also keeping you up to date with new advances in the science and art of pediatric practice. Authoritative and reader-friendly, it delivers the information you need in a concise, easy-to-use format for everyday reference and study. From rapidly changing diagnostic and treatment protocols to new technologies to the wide range of biologic, psychologic, and social problems faced by children today, this comprehensive reference keeps you on the cutting edge of the very best in pediatric care. - Includes more than 70 new chapters, including Postural Orthostatic Tachycardia Syndrome (POTS), Rare and Undiagnosed Diseases, Approach to Mitochondrial Disorders, Electronic Nicotine Delivery Systems, Zika, update on Ebola, Epigenetics, Autoimmune Encephalitis, Global Health, Racism, Media Violence, Strategies for Health Behavior Change, Positive Parenting, and many more. - Features hundreds of new figures and tables throughout for visual clarity and quick reference. - Offers new and expanded information on CRISPR gene editing; LGBT health care; gun violence; vaccinations; immune treatment with CAR-T cells; new technology in imaging and genomics; new protocols in cancer, genetics, immunology, and pulmonary medicine; and much more. - Provides fresh perspectives from four new associate editors: Nathan J. Blum of The Children's Hospital of Philadelphia; Karen Wilson of Mt. Sinai School of Medicine in New York; Samir S. Shah of Cincinnati Children's Hospital Medical Center; and Robert C. Tasker of Boston Children's Hospital. - Remains your indispensable source for definitive, evidence-based answers on every aspect of pediatric care.