  In this talk I review the structure of vacua of N=2 theories broken down to
N=1 and it's link with factorization of Seiberg-Witten curves. After an
introduction to the structure of vacua in various supersymmetric gauge
theories, I discuss the use of the exact factorization solution to identify
different dual descriptions of the same physics and to count the number of
connected domains in the space of N=1 vacua.
