The Integrated Density of States

This chapter is entirely devoted to the study of the so-called integrated density of states. It is an object of interest for various reasons. It is of physical importance for it can be measured experimentally in some cases. On the top of its physical appeal, the integrated density of states is a very interesting mathematical object which deserves to be investigated for its own sake. Many challenging mathematical problems remain open in this respect. Finally, several proofs of technical results crucial to the study of the spectral properties of the random Hamiltonians, and in particular of the localization, rely very heavily on estimates of the integrated density of states.