Optical spectral parameters of stratus clouds (single scattering albedo and optical thickness, as well as scattering and absorption coefficients) in shortwave spectral region are important as input parameters for many problems of atmospheric optics and climate. Here we analyze the results obtained from airborne, ground-based, and space measurements at different geographical sites for more than 30 years. Optical parameters were reconstructed from observations of hemispherical fluxes and intensity of solar radiation using analytical solution of the inverse problem. Spectral dependence, vertical profiles, and geographic distribution of optical parameters of stratus clouds are presented. Three main types of the clouds with weak, intermediate, and strong light absorption are revealed. Noticeable dependence of the volume scattering coefficient on the radiation wavelength is found.