  The aim of these notes is to provide a short introduction to supersymmetric
theories: supersymmetric quantum mechanics, Wess-Zumino models and
supersymmetric gauge theories. A particular emphasis is put on the underlying
structures and non-perturbative effects in N=1, N=2 and N=4 Yang-Mills
theories. (Extended version of lectures given at the TROISIEME CYCLE DE LA
PHYSIQUE EN SUISSE ROMANDE)
