This book includes a set of selected best extended papers from the 13th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH 2023), that was held in Rome, Italy, from July 12 to 14. The conference brought together researchers, engineers, and practitioners interested in methodologies and applications of modeling and simulation. New and innovative solutions are reported in this book. A selection was made after the conference, based also on the conference chairs assessment, reviewers' assessment, quality of presentation, and audience interest, so that this book includes the extended and revised versions of the very best papers of the conference. New and innovative solutions are reported in this book.