The emerging discipline of modeling and simulation in engineering is influenced by developments in system theories, artificial intelligence and software intelligence. Engineering modeling is an interdisciplinary field which includes concepts and techniques from mathematics, computer science, and management. It describes the design and conceptualization of large mechanical systems using complex non-linear models. It is useful to apprehend efficient numerical modeling along with model verification and validation. This book focuses upon the modeling theory and methodology of complex systems, simulation technology and approximation theory. It encompasses advanced and innovative modeling approaches and numerical strategies that would provide a comprehensive overview of the field to students, researchers and engineers.