Themistocles M Rassias is Professor at the National Technical University of Athens, Greece. He has published more than 300 papers, 10 research books and 45 edited volumes in research Mathematics as well as four textbooks in Mathematics (in Greek) for university students. He serves as a member of the Editorial Board of several international mathematical journals. His work extends over several fields of mathematical analysis. It includes nonlinear functional analysis, functional equations, approximation theory, analysis on manifolds, calculus of variations, inequalities, metric geometry and their applications. He has contributed a number of results in the stability of minimal submanifolds, in the solution of Ulam’s Problem for approximate homomorphisms in Banach spaces, in the theory of isometric mappings in metric spaces and in complex analysis (Poincaré’s inequality and harmonic mappings).