Wireless sensor/actuators networks (WSANs) are being increasingly used in a panoply of applications, such as industrial automation, process control, ambient assisted living, structural health monitoring, and homeland security. Most of these applications require specific quality-of-service (QoS) guarantees from their underlying communication infrastructures (regardless of their wireless, wired, or hybrid nature). This book gathers together an extremely rich set of contributions, addressing several WSAN domains and sharing QoS as a common denominator. Eight papers have made it through a rigorous and iterative peer review process (three reviews per paper, at least two review rounds), involving 38 authors from all over the world (North and South America, Europe, Asia, and Australia) from academia, industry, and the military. Each paper features at least one reference author which is highly reputed in this scientific domain, totaling over 100,000 citations altogether.