Severe acute respiratory syndrome (SARS) was first recognized in China in November 2002 and was subsequently associated with a worldwide outbreak involving 8098 people, 774 of whom died. The outbreak was declared contained on July 5, 2003, after the last human chain of transmission of SARS had been broken. Whether outbreaks of SARS will return is debatable, but no one disagrees that it is important to be prepared for this possibility. This article presents an overview of the transmission and control of SARS based on the current state of knowledge derived from published studies of the outbreak and on our own personal experience.