The National Institutes of Health (NIH) is a part of the U.S. Department of Health and Human Services and is the primary agency for conducting and supporting medical research in the United States. Established in 1887, it aims to improve public health through scientific discovery and innovation. The NIH funds a wide range of research projects and provides resources to researchers across the country. NIH is composed of 27 different institutes and centers, each focusing on specific areas of health and disease. These include the National Cancer Institute, National Heart, Lung, and Blood Institute, and National Institute of Allergy and Infectious Diseases. Through its efforts, the NIH plays a crucial role in advancing medical knowledge and improving healthcare outcomes.