Festkörperprobleme XI: Advances in Solid State Physics reviews advances in solid state physics and covers topics ranging from localized vibrational modes in semiconductors to isoelectric impurities in semiconductors, deep impurities, and liquid crystals. Elastic and inelastic electron tunneling through potential barriers in solids is also discussed, along with plasma physics and astrophysics. This book is comprised of 14 chapters and begins with a review of the theoretical and experimental requirements for the observation of high frequency, localized vibrational modes of impurities in a crystal lattice. The reader is then introduced to the properties of deep impurity levels in semiconductors. Some typical examples of isoelectronic impurities are presented, and theories of isoelectronic traps are considered. Subsequent chapters focus on the properties of the various types of liquid crystalline phases (nematic, cholesteric, and smectic); a few astrophysical problems for which the properties of the astrophysical plasma are important; and the use of stochastic models to probe the kinetics of phase transitions. Experimental results for elastic and inelastic electron tunneling through potential barriers in solids are also presented. This monograph will be of interest to physicists.