1. Introduction: open and periodic boundary conditions, reciprocal space, Brillouin zone, symmetry; basis sets -- gaussian, plane waves, grids; total energy methods, exchange-correlation hole.

2. Mean field methods: Hartree-Fock, integrals, convergence and corrections.

3. Correlated methods: perturbation theory and diagrams; other approaches; cusp and methods for treating it; integrals, convergence and corrections; canonical expressions for the correlation energy and reformulations using e.g. Laplace transform.

4. Locality of correlations: density matrix; localisation of states and projection on local basis; embedding; asymptotic convergence of long range correlations.

The lectures aim at introducing the theoretical grounds and basic concepts behind development and application of advanced quantum chemistry methods to molecules and extended systems. The lectures are suited for Master and PhD students.