The United States Military has become increasingly dependent upon technology to meet its mission objectives with a consequence being greater dependence on civilian defense contractors to provide specialized services in support of high-tech mission requirements. Modern military defense contractors have also become dependent upon reliable and secure information technology (IT) resources, and as a result adversaries continue to work toward increasing their abilities to launch attacks against critical electronic data (CED). This study was focused upon a known problem relating to the loss of critical electronic data (CED) from United States defense contractors as a result of disaster, cyber-attack, and trusted insiders. This study addressed the perceptions of risk regarding the loss of CED from United States defense contractors that results from the threat of disaster, cyber-attack, and trusted insiders. The purpose of this qualitative single site case study was to examine the threat perceptions that relate to loss of CED at risk from disaster, cyber-attack, and insider threat among a representative sample of U.S. defense contractors. The sample was drawn from U.S. defense contractors in the United States Midwest who were currently in an information technology and security (IT/S) functional position with at least five years of defense contractor IT/S experience which included day-to-day responsibility for protecting CED against loss. The CED risk perceptions of U.S. defense contractors that result from disaster, cyber-attack, and insider threat were exposed to the researcher using unstructured interviews which allowed the researcher to gain increased understanding and clarification of participant accounts and descriptions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]