Radiation Monitoring Devices, Inc. (RMD), Watertown, MA, specializes in  the research and development of high performance optical, X-ray, and  nuclear sensors.  This talk will give an overview of the company’s R&D activities, focusing primarily on technologies applicable to nuclear, synchrotron, and  high-energy physics experiments, including avalanche photodiodes, solid  state photomultipliers, photocathodes, semiconductor nuclear sensors, and scintillators.  Applications of these devices include searches for dark matter, spectroscopy for elementary particle analysis, time resolved X-ray diffraction studies, microstructure analysis, neutron imaging, and non-crystalline biological systems.