Functional methods and effective field theories

After a brief review of the main problems of Canonical Quantization, we examine two possible alternative approaches that may solve part of the problems. First we present little known functional techniques with the hope that they may improve our general understanding of QFT; second we study the Wilsonian approach, focusing in particular on the Wetterich equation. In the last chapter we discuss the Seiberg-Witten model to show the power of the Wilsonian approach.