Dr. Victor I. Sapritsky has worked in the areas of optical radiometry, radiation thermometry, and photometry since 1971. Currently, he is the world-leading expert in these areas and Deputy Head for Research of the Division of the Optical Radiometry of Incoherent Radiation at the All-Russian Institute of Optical and Physical Measurements (VNIIOFI), Moscow, Russia. Dr. Sapritsky is the developer of the national photometric, spectrophotometric, and blackbody-based radiometric standards of the Russian Federation and the former USSR. He is author of more than 200 research papers on optical radiometry, photometry, radiation thermometry, and calibration of space-born radiometric sensors.  Dr. Alexander Prokhorov has worked in the same areas since 1980. He participated in development and metrological certification of the national radiometric and photometric standards of the Russian Federation and the former USSR. He is a developer of many world-recognized software tools for computer modeling of blackbody radiation sources, and the world-leading expert in the theoretical and computational problems of optical radiometry, radiation thermometry, and photometry. In 2000–2009, he was a Guest Researcher at the National Institute of Standards and Technology (Gaithersburg, MD). Currently, he is President of Virial International, LLC (www.virial.com), the only company that develops software and offers various services in areas of optical radiometry, photometry, and radiation thermometry. Dr. Prokhorov is the author of more than 50 research papers in these areas.