The goal of this monograph is to summarize the different quantum mechanical methods developed in the last 20 years to treat the electronic structure of polymers. Owing to the nature of the problem, these methods consist of a mixture of quantum-chemical and solid-state physical tech niques. The theory described in Part I treats, besides the Hartree-Fock problem, the. electron correlation, and it has also been developed for disordered polymeric systems. Though for obvious reasons the book could not include all the existing calculations, each new method des cribed is illustrated by a few...