The NATO Advanced Study Institute on "Interfaces, Quantum Wells and Superlattices" was held from August 16th to 29th, 1987, in Banff, Alberta, Canada. This volume contains most of the lectures that were given at the Institute. A few of the lectures had already been presented at an earlier meeting and appear instead in the proceedings of the NATO Advanced Study Institute on "Physics and Applications of Quantum Wells and Super lattices" held in Erice...