"A Brief Course in Theoretical Physics . Quantum Mechanics" is an outstanding work created by two great scientists, Lev Davidovich Landau and Evgeny Mikhailovich Lifshitz .. This book is part of the famous multi-volume course that became the basis for the study of theoretical physics in the Soviet Union and beyond. In it, the authors strive to convey to the reader the complex concepts of quantum mechanics with clarity and accessibility, which makes it an indispensable tool for students, graduate students and anyone interested in physics at a deep level. The book covers a wide range of topics, ranging from the basics of quantum mechanics to more complex aspects such as quantum states and operators. Landau and Lifschitz use their unique style of presentation, which combines rigorous scientific accuracy and intuitive understanding. They not only explain the theoretical foundations, but also offer many examples and tasks, which allows the reader to consolidate the knowledge gained in practice. This makes the book not only a textbook, but also a real guide to the world of quantum physics. Who can like this book? First of all, it will be of interest to students of physics and mathematics, as well as graduate students who seek to deepen their knowledge in the field of theoretical physics . However, not only professionals will find value in it .. Science lovers who want to understand how the world works on a microscopic level will also be able to extract a lot of useful information from the pages of this work. The book is suitable both for those who are just beginning to get acquainted with quantum mechanics, and for more experienced readers who want to refresh their knowledge and look at familiar things from a new point of view. The topics raised in the book are relevant and important for the modern scientific community. Quantum mechanics is not just a branch of physics, it is the basis for understanding the many processes occurring in nature. The book explores key concepts such as the uncertainty principle, superposition of states, and quantum entanglement. These ideas not only form the basis for further study of physics, but also influence the development of technologies such as quantum computers and quantum cryptography. The style of Landau and Lifshitz is clear and logical, which makes their work easy to understand, despite the complexity of the topics discussed. Their approach to learning has inspired generations of scientists and students. In addition, their other well-known works, such as "A Brief Course in Theoretical Physics . Statistical Physics" and "A Brief Course in Theoretical Physics. Electrodynamics” is also worthy of attention and is a logical continuation of the study of physics. Short Course in Theoretical Physics . Quantum Mechanics is not just a textbook, it is a real find for anyone who wants to understand the laws that govern our world. It is able to inspire further research and discoveries, as well as give the reader a deep understanding of quantum reality. If you are looking for a high-quality and deep tutorial on quantum mechanics, this work will become your reliable companion in the world of theoretical physics.