This book introduces a new explanatory cross-layer model specifically designed to understand all aspects of ad hoc and sensor networking, from design through performance issues to application requirements. Future directions, challenges and potential simulation projects are also discussed.The topics included represent a significant portion of what is going on in academia and industry. The vast materials provided will enable readers to not only understand and position themselves in this hot area, but also to develop new capabilities, enhance skills, share expertise, consolidate knowledge and design future solutions. Thus, the book is useful for researchers and engineers, and anyone who seeks a deeper understanding of this growing field and wishes to pursue it as a future research topic.