There is an immediate requirement for Law Enforcement and Homeland Security to identify concealed weapons which may present a threat to official personnel and the general public. This involves suicide bomb vests, handguns, knife blades, and other threatening weapons. The weapons may be composed of a large range of materials such as metals, non-metals, plastics and explosives. The Homeland Security Advanced Research Projects Agency (HSARPA) and the National Institute of Justice (NIJ) are presently funding programs collectively covering all relevant portions of the electromagnetic spectrum and ultrasound in order to detect these weapons through the various materials that may be used to conceal these weapons This paper will outline the various imaging techniques being investigated and present results where available