This collection of 18 research papers, dedicated to Pierre Lelong, describes the state of the art on representative problems of complex analysis and geometry. The book opens with an exposition of the achievements of Pierre Lelong on plurisubharmonic functions, closed positive currents, and their further study by other mathematicians. Moreover, a list of eleven open problems is given. All other contributions contain new results related, for example, to the following items: - Capacities, product of positive currents, L2 extension theorems, Bergman kernels and metrics, new properties of convex domains of finite type - Non-compact boundaries of Levi-flat hypersurfaces of C2, compact boundary problems as application of compactly supported measures orthogonal to polynomials, Hartogs' theorem on some open subsets of a projective manifold, Malgrange vanishing theorem with support conditions - Embeddings for 3-dimensional CR-manifolds, geometrization of hypoellipticity, stationary complex curves and complete integrability - Regular polynomial mappings of Ck in complex dynamics, a direct proof of the density of repulsive cycles in the Julia set. The book is aimed at researchers and advanced graduate students in complex and real analysis, algebraic geometry and number theory.