The Seiberg-Witten Equations and Applications to the Topology of Smooth Four-Manifolds. (Mn-44), Volume 44The recent introduction of the Seiberg Witten invariants of smooth four manifolds has revolutionized the study of those manifolds. The invariants are gauge theoretic in nature and are close cousins of the much studied SU(2) invariants defined over fifteen years ago by Donaldson. On a practical level, the new invariants have proved to be more powerful and have led to a vast generalization of earlier results. This book is an introduction to the Seiberg