The book “Operational management in power systems . At 4 p.m.. H. 4 Prevention and elimination of emergency modes” by Evgeny Valentinovich Kalentionka is the final part of a large-scale study devoted to the most important aspects of power system management . This work, like the previous parts, is aimed at a deep understanding and analysis of the processes related to ensuring the reliability and security of energy supply in the modern world. In the fourth part, the author focuses on a critical topic - the prevention and elimination of emergency modes in power systems. The reader is immersed in a world of complex technical solutions and strategies that help minimize the risks and consequences of emergency situations. Kalentionok shares her knowledge and experience, emphasizing that effective management in power systems requires not only theoretical knowledge, but also practical skills, as well as the ability to respond quickly to unforeseen circumstances. The book will be of particular interest to specialists in the field of energy, engineers, students of technical universities, as well as anyone who seeks to better understand how modern power systems operate. It is suitable for both professionals with experience in this field, and for beginners who are just starting their way in the world of energy. In it you will find many examples, illustrations and practical recommendations that will help you better absorb the material. The topics raised in the book cover a wide range of issues, ranging from analysis of the causes of accidents to methods of preventing them. Calentionok emphasizes the importance of a systematic approach to management, which includes not only technical, but also organizational aspects. The reader will be able to learn about modern monitoring and diagnostics technologies, as well as how the introduction of innovative solutions can significantly improve the reliability of power systems. The author's style is distinguished by clarity and accessibility, which makes complex technical concepts understandable to a wide audience. Calentionok is known for his scientific works in the field of energy and management, and his work is respected among colleagues and students. In the previous parts of this series, he has already considered such important aspects as planning and organization of operational management, which creates a solid foundation for understanding the topics discussed in the fourth part. The book “Operational management in power systems . At 4 p.m.. H. Prevention and elimination of emergency modes” will be an indispensable tool for anyone interested in the sustainability and safety of energy systems. Not only will it enrich your knowledge, but it will also help you develop the critical thinking necessary to solve complex problems in this field. If you are looking for literature on the topics of power system management, emergency safety or just want to expand your horizons in the field of energy, this book will be an excellent choice. Read, study and apply the knowledge gained in practice to contribute to the development of safe and efficient energy systems of the future.