PERSEREC developed an unclassified database of Americans involved in espionage against the United States since 1945, and in 1992 published a report on it entitled Americans Who Spied Against Their Country Since World War II. The goal of the original project was to analyze the cases in terms of themes and trends that would further our understanding of the phenomenon of espionage. Since 1992, further instances of espionage by American citizens have come to light, and we have continued to enter them into an espionage database. An updated analysis incorporating recent cases seemed useful. In this...