This is the second MRS book to focus on semiconductor radiation detectors for use in the energy range of a few eV to 5 MeV. The primary emphasis is on developing semiconductor X-ray and gamma-ray detectors and imagers which combine the advantages of room-temperature operation with the excellent energy resolution of cryogenically cooled spectrometers. By eliminating the cryogen, new radiation-sensing instruments, such as spectrometers and imagers, can be manufactured that are portable, easy to operate, and relatively maintenance-free. Medical systems, industrial process monitoring, baggage scanning, and environmental remediation are fields where these systems are finding increased commercial application. Topics include: cadmium zinc telluride growth and materials properties; cadmium zinc telluride detectors and systems; cadmium telluride materials, detectors and systems; mercury and lead iodide materials, detectors and systems; Group IV and III-V materials, detectors and systems; ZnSe and ZnS materials and detectors; analysis and characteristics of detectors, systems and applications and IR materials and detectors.