Theoretical Physics . Volume 3. Quantum Mechanics (non-relativistic theory) by Lev Davidovich Landau and Evgeny Mikhailovich Lifshitz is an outstanding work that occupies a special place in the world of scientific literature. This volume is part of the famous multi-volume course, which covers the main aspects of physics and is a reference book for students, graduate students and professionals in the field of physics. Quantum mechanics is one of the most mysterious and at the same time fascinating areas of physics, and in this volume Landau and Lifschitz masterfully reveal its foundations. The authors begin by discussing the principles underlying quantum mechanics and gradually delve into more complex topics such as wave function, operators, measurements, and interpretations of quantum theory. Each chapter is imbued with a deep understanding of the subject and the desire to make complex concepts accessible to the reader. Landau and Lifschitz use a clear and concise style, which allows even those who are just beginning to get acquainted with quantum mechanics to immerse themselves in the study of this exciting science. The book will be of interest not only to physics students, but also to everyone who is passionate about science and wants to understand how the world works at the most fundamental level. It is suitable for both those who study physics at the undergraduate level and for graduate students seeking to deepen their knowledge. It can also attract the attention of researchers and teachers who are looking for high-quality and deep sources for their research and lectures. The topics raised in the book go beyond purely scientific questions. The authors discuss philosophical aspects of quantum mechanics, such as the nature of reality, the role of the observer, and the concept of probability. These reflections make the book not only a textbook, but also a real philosophical treatise that encourages the reader to think about deeper questions of existence and knowledge. Lev Landau, Nobel Prize winner, is known for his unique approach to teaching and research. His style is distinguished by clarity and rigor, which makes his work especially valuable. Evgeny Lifshitz, in turn, is also an outstanding physicist and teacher who has made a significant contribution to the development of physical education in Russia. Their joint work in this book is not just a presentation of the theory, but also an attempt to convey the spirit of science, its beauty and complexity. Theoretical Physics . Volume 3. Quantum mechanics (non-relativistic theory)” will become an indispensable assistant for all who seek to understand the quantum world It not only enriches the reader’s knowledge, but also inspires further research and discovery. If you are interested in such works as “Quantum Mechanics and the Way to Reality” by David Deutsch or “Quantum Physics for Beginners” by John Griffith, then this book should definitely take a worthy place on your shelf. In conclusion, “Theoretical Physics . Volume 3. Quantum mechanics (non-relativistic theory) is not just a textbook, but a real encyclopedia of knowledge that can change your perception of physics and open new horizons in understanding the laws of nature. Do not miss the opportunity to immerse yourself in the exciting world of quantum mechanics with Landau and Lifshitz!