The stability analysis of complex systems provides the principles and methods useful for engineers, mathematicians, economists, physicists, biologists, and sociologists among others to obtain a better understanding of the dynamics of the system. The stability analysis of non-linearity and delays continues to present challenges of interest which contribute in the current and future investigations to most application domains including industry, energy, agriculture, sustainability, mechatronics, communications technologies and autonomous systems.

In recent decades, attempts have been made to explain the rich behavior of nonlinear systems to design and manufacture new devices that can operate more efficiently and give rise to emerging technologies. In trying to understand the complex behavior of dynamic systems, scientists and engineers across many different disciplines have faced the problem of proposing new controllers or improving control designs, optimizing or increasing performance. We can highlight that those controllers for delay systems are particularly important because such delay can cause critical and dangerous instabilities. The challenge is to develop a controller that has the capacity of driving the system to a stable operating point, regardless of the delay.

The aim of this Special Issue is to provide to readers new tools and recently advances developed about complex nonlinear systems and complex systems with delay. Audience includes all researchers and graduate students, theorists and applied, interested in complex systems and control theory. We invite the authors to contribute original research articles that describe novel results for nonlinear or delay complex systems.

Potential topics include but are not limited to the following:

• Complexity and retarded control
• Nonlinear and Delayed Systems
• Mechatronics and Automation
• Autonomous Systems
• Under-Actuated Systems
• Distributed networked control systems
• Industrial Applications
• Stability of nonlinear dynamical systems
• New chaotic systems and synchronization of a pair of couple systems