The book "General Fourier series theory", written by outstanding Russian mathematicians Ilin and Moiseev, is a deep and fascinating immersion in the world of mathematical analysis and function theory. This work will certainly become a reference book for students, graduate students and teachers, as well as for anyone interested in mathematics and its applications in various fields of science and technology. The book focuses on the Fourier series, a powerful tool that allows periodic functions to be broken down into series, which in turn opens the door to an understanding of complex processes occurring in nature and technology. The authors seek not only to explain the theoretical foundations, but also to demonstrate the practical application of Fourier series in various fields, such as physics, engineering, and even economics. The reader will be able to see how mathematical concepts come to life in real problems, which makes studying the material especially fascinating. The book will be interesting not only for students of mathematical and physical specialties, but also for those who already have experience in mathematics and want to deepen their knowledge. It is suitable for both beginners and more experienced readers who seek to expand their horizons in analysis and function theory. If you are looking for literature that will help you understand how Fourier series can be used to solve practical problems, this book will be a real find for you. The topics raised in the "General Fourier Series Theory" cover a wide range of issues, including series convergence, properties of trigonometric functions, and their application in various fields. The authors pay special attention to the intuitive understanding of the material, which makes complex concepts accessible to perception. The book also contains many examples and tasks that will help the reader to consolidate the knowledge gained and put it into practice. The style of writing Ilyin and Moses is clear and logical, which makes it easy to follow the course of thought of the authors. Their approach to the presentation of the material makes the book not only a textbook, but also a fascinating reading for anyone interested in mathematics. In addition, both authors have extensive experience in teaching and research, which gives their work additional value. If you are looking for similar works, pay attention to the books "Mathematical Analysis" and "Theory of Functions of a Complex Variable" These papers will also help you deepen your knowledge of analysis and broaden your understanding of mathematical concepts. "General Fourier series theory" is not just a textbook, but a real encyclopedia of knowledge that will help you discover the world of mathematical analysis. It will be your reliable companion in the study of complex topics and will help you develop analytical thinking. Do not miss the opportunity to immerse yourself in this fascinating world with Elijah and Moses!