This book gives an overview on mid-infrared optical glass and fibers laser, it cover the underlying principle, historic background, as well as recent advances in materials processing and enhanced properties for rare earth doped luminescence, spectroscopy lasers, or optical nonlinearity applications. It describes in great detail, the preparation of high purity non-oxide IR glass and fibers to be used as mid-IR fiber laser and supercontinuum sources for optical fiber spectroscopy. It will be useful for academics, researchers and engineers in various disciplines who require a broad introduction to the subject and would like to learn more about the state-of-the-art and upcoming trends in mid-infrared fiber source development, particularly for industrial, medical and military applications.