In the first part of this lecture the standard methods for describing the electronic structure of molecular and supermolecular systems will be reviewed. The basic theoretical methodologies, the standard approximations, common implementations and the limitations of modern methods will be discussed.

In the second part very recent developments in theoretical chemistry and molecular physics will be presented. The new generation of electronic structure methods has the potential to accurately describe complex systems and phenomena. The underlying evolution of methods will be discussed and various examples of recent applications of novel methods to problems from physics and chemistry will be presented.