The last two decades have witnessed a great deal of interests in sensor/actuator networks (SANs), or, generally, networked control systems (NCSs). Compared to conventional system architectures, NCSs have numerous advantages such as reduced systemwiring, being easier for design, diagnosis, and maintenance, lower cost, and increased flexibility, reliability, and safety. As a result, NCSs have been widely applied to many areas, for example, automobiles, aircrafts, and spacecrafts, autonomous vehicles, transportation systems, power systems, remote monitoring and data acquisition systems, chemical processes, and many manufacturing plants. Research on NCSs has heretofore focused mainly on several basic communication constraints that can cause performance degradation or stability loss, such as network-induced delays, packet dropouts, data corruptions or disordering, and data rate limitation and quantization effects. Medium access constraint is another important issue worthy of intensive investigation, which refers to the fact that the network cannot accommodate all the nodes (sensors, actuators, subsystems, etc.) simultaneously at any time. There are other open issues awaiting investigation, too. As a special type of NCSs, sensor/actuators networks typically have a large number of devices advanced in sensing, communicational, computational, and mobility capabilities, demanding nontrivial energy. In addition, the batteries powering these devices have limited capacity and cannot be replaced or recharged conveniently. As a consequence, many interesting and challenging issues are open, for example, localization, coverage and routing of mobile sensor/actuator networks, and so forth. The special issue focuses on the state-of-the-art research and development in the analysis and design for networked control systems as well as the theoretical and technological advances in sensor and actuator networks. The intention of this special issue was to provide for researchers a forum to share their latest research results on filtering, estimation, control, and other aspects in sensor/actuator networks and networked control systems and for readers an opportunity to have an overview of the latest achievements about some interesting issues this field has been encountering. In the next section, we give a brief description of the papers in this special issue.