The idea of this book comes from the observation that sensor networks represent a topic of interest from both theoretical and practical perspectives. The title und- lines that sensor networks offer the unique opportunity of clearly linking theory with practice. In fact, owing to their typical low-cost, academic researchers have the opportunity of implementing sensor network testbeds to check the validity of their theories, algorithms, protocols, etc., in reality. Likewise, a practitioner has the opportunity of understanding what are the principles behind the sensor networks under use and, thus, how to properly tune some accessible network parameters to improve the performance. On the basis of the observations above, the book has been structured in three parts:PartIisdenotedas"Theory,"sincethetopicsofits vechaptersareapparently "detached" from real scenarios; Part II is denoted as "Theory and Practice," since the topics of its three chapters, altough theoretical, have a clear connection with speci c practical scenarios; Part III is denoted as "Practice," since the topics of its ve chapters are clearly related to practical applications.