  The main goal of electronic structure methods is to solve the Schroedinger
equation for the electrons in a molecule or solid, to evaluate the resulting
total energies, forces, response functions and other quantities of interest. In
this paper we describe the basic ideas behind the main electronic structure
methods such as the pseudopotential and the augmented wave methods and provide
selected pointers to contributions that are relevant for a beginner. We give
particular emphasis to the Projector Augmented Wave (PAW) method developed by
one of us, an electronic structure method for ab-initio molecular dynamics with
full wavefunctions. We feel that it allows best to show the common conceptional
basis of the most widespread electronic structure methods in materials science.
