Embedded network systems (ENS) provide a set of technologies that can link the physical world to large scale networks for such purposes as monitoring of borders, infrastructure, health, the environment, automated production, supply chains, homes, and places of business. ENS nodes integrate the novel combination of signal processing, communication, sensing, and actuation technology. Their composition into large networks requires knowledge of networking and distributed software systems. Many excellent textbooks exist that treat these topics separately, and there are corresponding undergraduate and graduate courses. However, these provide both too much information on some topics and not enough on others for a course specifically devoted to ENS. The purpose of this book is to provide support for senior design courses and introductory graduate courses in ENS without the requirement for students to have expertise in all of these areas. As such it can also serve as a resource for the practicing professional in this rapidly expanding area of research and enterprise. Note what the book is not: a comprehensive and objective treatment of the latest developments in sensor networks. We do not presume to compete with the varied riches offered on the worldwide web by what is now a large and very creative group of researchers around the world. Therefore our focus is consciously on principles and methods which have proven useful to us in the course of designing multiple generations of ENS (research, commercial products, class projects), with digressions to what in our opinion are interesting topics for new investigations.