This historical presentation focuses on yellow fever, and some of the events by which the veil of this terrible scourge was lifted. There are three main parts to the talk. First, I will present a brief history of the disease and its impact on society in the United States. Second, I will discuss beliefs regarding the possible origins and causes of yellow fever that were prevalent around 1900, and will outline the experiments performed in Cuba by Major Walter Reed and his colleagues Dr. Jesse Lazear, Dr. James Carroll, and Dr. Aristides Agramonte. These simply elegant studies, the first to use informed consent of research subjects, elucidated the mode of transmission of yellow fever. The third section discusses several topics including the global importance of this research; aftermath of the Reed Board’s work; and fate of the Board members as well as some of the research volunteers.