English: This historic photographic depicted Dr. Alexander D. Langmuir (1910 - 1993), seated to the right of Ms. Ida Sherwood during an Epidemic Intelligence Service (EIS) luncheon. Dr. Langmuir was chief epidemiologist at the Centers for Disease Control and Prevention for two decades. Dr. Langmuir founded the Disease Investigations branch of the Epidemic Intelligence Service (EIS) in 1951. He was a strong proponent of "shoe leather" epidemiology--an intense focus on the people and places where the disease outbreaks actually occurred, and the precise gathering of statistics to support whatever action was needed. In starting the CDC EIS program, his goal was to introduce professionals from medicine and relevant social sciences to the science of epidemiology in the hope that they would become well educated in the practice of public health. As a result, many of these “disease detectives” continued on in the field of epidemiology, while others carried that knowledge with them into whatever careers they chose, as advocates for sound public health practice.