The book "Online Optimization of Large Scale Systems" by Martin Grötschel offers a comprehensive analysis of mathematical optimization in the context of large systems. It highlights the development of mathematics from its beginnings to its role as a crucial language of science. In particular, the importance of mathematical optimization for decision-making is emphasized, with various practical application examples presented. The challenges arising from incomplete models and unpredictable data are thoroughly addressed. The book provides solutions for complex problems, such as the efficient control of elevators, the adjustment of airplane wings under varying conditions, the navigation of robots in unknown environments, and the response of power plants to rapidly changing energy demands. With 804 pages, it offers a solid foundation for professionals and students interested in the optimization of large systems.