Dynamical network systems, such as gene network systems, biological network systems, neural network systems, and so on, are a class of nonlinear complex systems, which consist of large-scale interconnected dynamic nodes that are described by the basic units of the physical network. As a basic unit of the network, each node can have a specific dynamic behaviour, but the whole network may present different complex dynamics.

Synchronization, state estimation, observer design, and application of dynamic network systems are of great significance, and they have made considerable contributions to other research fields such as intelligent control, signal processing, communications, computers, and so on. In the future, the research of dynamic network systems will have better prospects.

The objective of this Special Issue is to provide a comprehensive collection of cutting-edge research work on the synchronization, state estimation, observer design, and application in engineering of dynamical network systems. Original research articles presenting novel in-depth fundamental research are welcomed, along with review articles discussing the current state of the art.

Potential topics include but are not limited to the following:

• Synchronization, nonlinear control, and estimation of dynamical networks systems
• Observability, computability, and complexity of complex networks systems
• Dynamic analysis of stochastic networks and impulsive networks
• Verification, abstraction, and optimization of dynamical networks systems
• Neural or fuzzy approaches to hybrid dynamical network systems
• Synchronization of oscillators and chaotic network systems
• Fault diagnosis, dependability, and observer design of dynamical networks systems
• Neural dynamic approach for solving optimization problems
• Synchronization, nonlinear control, and estimation for cooperating robotic systems, interconnected electric power systems, interconnected financial systems, biosystems, and various cyber-physical systems