  The main subject of these lectures is the Nonperturbative Wave Functions. We
describe some nonperturbative methods (like QCD sum rules, dispersion
relations, duality etc) in order to study this object. We also consider some
applications of the obtained results, such as form factors, inclusive
amplitudes and diffractive electroproduction. Finally, we discuss the instanton
liquid model which may help us to understand the success of the constituent
quark model.
