A dozen years have passed since the publication of Murray Kleiner's seminal work Handbook of Polygraph Testing. The events of September 11, 2001 and heightened concerns about national security and terrorism have resulted in increased efforts to improve existing techniques for the assessment of credibility and develop new techniques for implementation in field settings. We are all aware of the massive expansion of costly government programs, such as the establishment of the Department of Homeland Security and Transportation Security Administration programs for screening airline passengers. However, many concerns have been voiced by scientists and the Government Accountability Office about the scientific basis for such programs and their effectiveness for identifying individuals who plan to harm people, property, and society.