The principal objective of this publication is the enhancement of security awareness among cleared employees and military service members by showing that espionage and similar prosecutable offenses involve real people in workplace situations like their own, and that loyal and conscientious employees continue to be the target of attempts by agents of foreign intelligence services to recruit them as sources of sensitive defense and intelligence information. The reader will recognize that these case summaries bear little resemblance to the glamorized fictional accounts of spy novels; rather, they often tell mundane tales of human folly resulting in tragic personal consequences. Many of the disasters described in these summaries might have been avoided if concerned coworkers, recognizing danger signs and personal vulnerabilities, had been willing to intervene. Other lessons that can be shared with employee audiences are that most offenders were trusted insiders, not foreign agents; even "friendly" countries have been the recipients of stolen US classified information; and these damaging betrayals can occur in either government or contractor organizations. In addition to serving the needs of the security educator, this publication through several editions since 1985 has been consistently in high demand as a reference source for security managers and policymakers and used in the training of counterintelligence and security professionals in government and industry. We hope that this latest release, Espionage and Other Compromises of National Security, will continue to meet these various needs.