In the late 1950's the lack of uniformity in reported performance data on infrared detectors indicated a need for a joint measurement standard. A working panel was established to prepare a suitable document dealing with definitions, measurement methods and data format. Their document Standard Procedure For Testing Infrared Detectors and For Describing Their Performance was subsequently published in September 1960. This standard has been widely used by the infrared community and it is considered the definitive document for detector testing. Over the past fifteen years many new detector materials, fabrication techniques and modes of operation have been developed. Detectors have been improved until the performance of several types of detectors approaches the theoretical limit. The availability of infrared lasers, sampling oscilloscopes, digital processing equipment, etc., has provided many new and useful detector measurement tools.