This book presents the super???eld description of various supersymmetric ???eld theory models in three- and four-dimensional space-times. A mapping between super???eld and component formulations of supersymmetric ???eld theories is discussed. The author also describes the methodology for calculating quantum corrections in these theories employing supergraph formalism and functional methods, and illustrates these approaches with many detailed examples of how such calculations are performed for various super???eld models.