O ne hundred years ago, in 1909, the American Society for Clinical Investigation (ASCI) held its first annual meeting. The founding members based this new society on a revolutionary approach to research that emphasized newer physiological methods. In 1924 the ASCI started a new journal, the Journal of Clinical Investigation. The ASCI has also held an annual meeting almost every year. The society has long debated who could be a member, with discussions about whether members must be physicians, what sorts of research they could do, and the role of women within the society. The ASCI has also grappled with what else the society should do, especially whether it ought to take a stand on policy issues. ASCI history has reflected changing social, political, and economic contexts, including several wars, concerns about the ethics of biomedical research, massive increases in federal research funding, and an increasingly large and specialized medical environment.