This book presents, in a unifying perspective, the topics related to N=2 supersymmetry in two dimensions. Beginning with the Kähler structure of D=4 supergravity Lagrangians, through the analysis of string compactifications on Calabi-Yau manifolds, one reaches the heart of the matter with the chiral ring structure of N=2 conformal field theories and its relation to topological field theory models and Landau-Ginzburg models. In addition, mirror symmetry, topological twists and Picard-Fuchs equations are discussed.