Knowledge of the refractive indices and absorption coefficients of semiconductors is especially important in the design and analysis of optical and optoelectronic devices. The determination of the optical constants of semiconductors at energies beyond the fundamental absorption edge is also known to be a powerful way of studying the electronic energy-band structures of the semiconductors. This text gives the reader tabulated values and graphical information on the optical constants of the most popular semiconductors, in order to develop an understanding of the optical response of crystalline and amorphous semiconductors over the entire spectral range. Device engineers, material scientists, solid strata physicists and students specializing in the fields of semiconductor physics and device engineering should find this a useful reference tool.