Mircea Sofonea earned his PhD from the University of Bucarest, Romania, and his habilitation at the Université Blaise Pascal of Clermont-Ferrand (France).He is currently a Distinguished Profesor of Applied Mathematics at the University of Perpignan Via Domitia, France and a honorary member of the Institute of Mathematics, Romanian Academy of Sciences. His areas of interest and expertise include multivalued operators, variational and hemivariational inequalities, solid mechanics, contact mechanics and numerical methods for partial differential equations. Most of his reseach is dedicated to the Mathematical Theory of Contact Mechanics, of which he is one of the main contributors. His ideas and results were published in nine books, four monographs, and more than three hundred research articles. Stanislaw Migórski earned his PhD degree and the habilitation from the Jagiellonian University in Krakow, Poland. He is currently a Full Honorary Professor and Chair of Optimization and Control Theory at Jagiellonian University in Krakow. His areas of interest and expertise include mathematical analysis, differential equations, mathematical modelling, methods and technics of nonlinear analysis, homogenization, control theory, computational methods and pplications of partial differential equations to mechanics. His research results are internationally recognized and were published in six books, four monographs, and more than two hundred research articles.