The Theory of Linear Operators in Hilbert Space by H. and . Achiezer and E. M. Glazman is a deep and systematic study of one of the most important sections of functional analysis. This work, released within the framework of classical mathematical literature, is intended for students, graduate students and specialists interested in modern methods of mathematical analysis and its applications in various fields of science and technology. In their book, the authors carefully consider the linear operators operating in Hilbert spaces and their properties. They not only explain basic concepts such as operator spectrum, self-adjoint and unitary operators, but also immerse the reader in more complex topics, including the theory of compact operators and their spectra. This makes the book a valuable resource for both theorists and practitioners who want to deepen their knowledge of mathematical physics and engineering. The book will be especially interesting for those who already have basic knowledge in the field of linear algebra and functional analysis, and want to expand their horizons. Graduate students of mathematical and physical faculties, graduate students and teachers, as well as researchers working in the field of applied mathematics, will find in it many useful ideas and methods that can be applied in their scientific activities. The topics raised in the book cover a wide range of issues, including operator theory, their applications in quantum mechanics, and other areas of physics. The authors also discuss the importance of Hilbert spaces in the context of modern mathematical research, which makes the book relevant and in demand in the scientific community. Readers will be able to see how abstract mathematical concepts find their application in real-world problems, which adds additional value to this work. The style of the authors is distinguished by clarity and rigor of presentation, which allows the reader to easily assimilate complex ideas and concepts. N. and . Ahiezer and E. M. Glazman famous mathematicians whose work has left a significant mark in the field of functional analysis Their previous works, such as "Methods of Functional Analysis" and "Operator Theory", have also earned recognition and have become classics of mathematical literature. In this book, they continue to develop their ideas, offering the reader a unique view of linear operators and their properties. If you are looking for literature that will help you to better understand linear operators in Hilbert spaces, this book will be an indispensable assistant for you. It will not only enrich your knowledge, but also inspire further research in functional analysis. Readers interested in mathematics, physics, and applied sciences will find in it many ideas and concepts that will help them in their studies and scientific work. Thus, the Theory of Linear Operators in Hilbert Space is not just a textbook, but a real treasure trove of knowledge that can open up new horizons for anyone who decides to plunge into the world of linear algebra and functional analysis. Do not miss the opportunity to get acquainted with this outstanding work, which will become your reliable companion on the way to understanding complex mathematical concepts.