On September 22-23, 2009, the National Research Council held a workshop on the field evaluation of behavioral and cognitive sciences—based methods and tools for use in the areas of intelligence and counterintelligence. Broadly speaking, the purpose of the workshop was to discuss the best ways to take methods and tools from behavioral science and apply them to work in intelligence operations. More specifically, the workshop focused on the issue of field evaluation—the testing of these methods and tools in the context in which they will be used in order to determine if they are effective in real-world settings. This book is a summary and synthesis of the two days of presentations and discussions that took place during the workshop. The workshop participants included invited speakers and experts from a number of areas related to the behavioral sciences and the intelligence community. The discussions covered such ground as the obstacles to field evaluation of behavioral science tools and methods, the importance of field evaluation, and various lessons learned from experience with field evaluation in other areas.