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.

PACS numbers: 11.30.Pl, 11.15.Tk