The Henry Draper Catalog is a comprehensive star catalog that classifies stars based on their spectral characteristics. Created by astronomer Henry Draper in the late 19th century, it includes detailed observations of over 10,000 stars. The catalog is significant for its role in the development of stellar classification systems. The catalog is organized into different spectral types, which help astronomers understand the physical properties of stars, such as temperature and composition. It laid the groundwork for future catalogs and studies, influencing the field of astrophysics and enhancing our knowledge of the universe.