**1. Aims, Scope, and Statistics of the Special Issue**

Complex systems have long been an integral part of modern life and can be encountered everywhere. A comprehensive study of such systems is a challenging problem, the solution of which is impossible without the use of contemporary mathematical modeling techniques. Mathematical models form the basis for optimal design and control of complex systems.

This Special Issue is focused on recent theoretical and computational studies of complex systems modeling, control, and optimization. Topics include, but are not limited to, the following themes:


Cross-border modeling and numerical simulation in Physics and Engineering are particularly welcome in this Special Issue.

In total, 31 manuscripts were submitted, and 20 papers by 49 authors were successfully published. Authors come from the following 11 countries:


A rose diagram of the number of unique authors from different countries is shown in Figure 1.

**Citation:** Posypkin, M.; Gorshenin, A.; Titarev, V. Preface to the Special Issue on "Control, Optimization, and Mathematical Modeling of Complex Systems". *Mathematics* **2022**, *13*, 2182. https://doi.org/10.3390/ math10132182

Received: 16 June 2022 Accepted: 20 June 2022 Published: 23 June 2022

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