This review volume contains articles on the recent developments, new ideas, as well as controversial issues dealing with the general phenomena of hopping transport in disordered systems. Examples of hopping systems of current interest are polymers and biological materials, mesoscopic systems, two- and one-dimensional systems such as MOSFETs, semiconductors near the metal-nonmetal transition, and the new high temperature superconducting materials (in their normal state). The fundamental problems addressed include effects of static and dynamic interactions with phonons, Coulomb interaction, new magnetic effects due to coherent scattering, effects of high electric fields, and relaxation phenomena.