The National Institutes of Health (NIH) is a key agency of the U.S. Department of Health and Human Services, responsible for biomedical and public health research. It plays a crucial role in advancing medical knowledge and improving health outcomes through funding and conducting research across various fields. NIH comprises 27 institutes and centers, each focusing on specific areas of health, such as cancer, heart disease, and mental health. By supporting innovative research and training the next generation of scientists, the NIH aims to enhance the nation's health and address pressing medical challenges.