Physical systems and information theory; algorithms - description and nature; synthetic nanostructures as quantum control systems; Langmuir-Blodgett techniques; spectroscopy of single molecules in solids; charging effects - single-electron tunnelling; dynamical repertoire of interacting networks; electron motion in lateral superlattices on semiconductors; controlled electronic transfer in molecular chains and segments; cooperative optical properties of interacting charge transfer subunits; ensemble properties and applications; electric field effects on persistent spectral hole burning and applications in photonics; persistent spectral hole burning and its application in optical data storage and processing; holographic spectral hole burning - from data storage to information processing; biomolecular electronics and optical computing; bacteriorhodopsin - optical processor molecules from nature?; prospects of molecular electronics.;Integrating molecular physics and information theory, this work presents molecular electronics as a method for information storage and retrieval that incorporates nanometer-scaled systems, uses microscopic particles and exploits the laws of quantum mechanics. It furnishes application examples employing properties of distinct molecules joined together to a macroscopic ensemble of virtually identical units.