Due to the more demanding and stringent requirements of detectability, the importance of stray light rejection has become a major driver in many instances. In the last ten years, great strides have been made in developing techniques for achieving higher stray light rejection, including analytical computer programs for analysis and experimental facilities for the measurement of these low light levels. The status of some of the problems, techniques, and experiences with the stray light problem is presented in this paper. One area of recent study is the effect of cryodeposition on scattering. The definitions of surface scattering, vital to the standardization of results are shown. Presently available analytical techniques including the software packages GUERAP and APART and the few experimental facilities capable of measuring the stray light rejection of a total sensor are summarized. A comparative study of the analytical and experimental tools is made by means of two specific examples of aerospace application.