The Theory of Variable Currents by B. Yu. Goryainov is a fascinating and deep immersion in the world of electrical engineering, which will be a real discovery for both students and professionals in the field of electric power and electrical engineering. This work is not just a textbook, but a whole encyclopedia of knowledge that covers all aspects of alternating current theory, from basics to complex concepts. The main theme of the book is the study of alternating currents, their properties and applications in modern electrical systems. Goryainov, with rich experience and deep knowledge in his field, offers the reader not only theoretical foundations, but also practical examples that help to better understand complex phenomena. The book deals with key issues such as the analysis of AC circuits, resonance phenomena, calculation methods and much more. Each section is written with clarity and logic, which allows the reader to easily digest the material and apply it in practice. This book will be especially interesting for students of technical specialties, graduate students and teachers, as well as anyone who wants to deepen their knowledge in the field of electrical engineering. If you are looking for a tutorial that not only explains the theory, but also demonstrates its application in real-world problems, AC Theory will become your reliable companion. It will also be useful to engineers and specialists working in the field of design and operation of electrical systems, who seek to improve their skills and expand their horizons. Goryainov raises important topics, such as the effect of alternating currents on electrical machines, converters, and control systems. He focuses on modern trends and technologies, which makes the book relevant and in demand. Readers will be able to learn about the new methods of analysis and design that are used in modern electrical installations. This is important in the context of the rapid development of technology and the need to adapt to new requirements. The author's style is characterized by accessibility and clarity, which makes complex topics understandable even for beginners. Goryainov uses many illustrations, graphs and examples, which creates a visual representation of the issues under consideration. His approach to learning is based on the principle of "from simple to complex", which allows the reader to gradually accumulate knowledge and confidently move to more complex concepts. Except for "Theory of alternating currents", B. Yu. Goryainov is the author of several other well-known works in the field of electrical engineering and the electric power industry, which also deserve attention. His works are distinguished by a high level of scientific validity and practical orientation, which makes them indispensable for the study of the subject. If you are looking for a book that will help you immerse yourself in the world of alternating currents, understand their nature and learn how to apply knowledge in practice, “Theory of alternating currents” Yu. This is what you need.. Do not miss the opportunity to expand your knowledge and skills in one of the most important areas of modern science and technology. This book will be your reliable assistant in studying the theory and practice of alternating currents, opening up new horizons and opportunities in the world of electrical engineering.