Theoretical Physics, Volume 4. Relativistic Quantum Theory, Part 1 by Lev Davidovich Landau and Evgeny Mikhailovich Lifshitz is an outstanding work that continues the traditions of classical physics and opens the door to the world of relativistic quantum theory. This volume is part of the famous "Theoretical Physics" series, which has served for decades as a reference book for students, graduate students and researchers in the field of physics. In this volume, the authors immerse the reader in a complex but fascinating world of relativistic effects that become especially relevant in the context of high energies and small scales. Landau and Lifschitz, with deep knowledge and a unique style of presentation, explain the basic principles of relativistic quantum mechanics, starting with the basics and gradually moving on to more complex topics. The reader will be able to learn about key concepts such as spin, antiparticles, interactions and many other aspects that form the basis of modern particle physics. This book will be interesting not only for students and graduate students of physics, but also for everyone who is passionate about science and seeks to understand how the laws of nature work at the most fundamental level. If you are interested in topics such as quantum mechanics, the theory of relativity or particle physics, then “Theoretical Physics, Volume 4” will be a real discovery for you. Readers who are already familiar with other volumes of this series will find in this book a logical continuation of their knowledge and an opportunity to deepen their understanding of complex physical phenomena. The topics raised in the book cover a wide range of issues related to relativistic quantum theory. The authors discuss not only theoretical aspects, but also the practical application of this knowledge in various fields of science. The book touches on important concepts such as symmetry, invariance, and particle interaction, making it particularly relevant in light of current research in high-energy physics and cosmology. The style of Landau and Lifshitz is clear and logical, which allows even complex ideas to be presented in an accessible and understandable way. Their ability to explain abstract concepts with simple examples and intuitive illustrations makes reading not only cognitive, but also fascinating. These authors are known for their other works, such as "Classical Physics" and "Quantum Mechanics", which have also become classics and are recognized worldwide. Their collaborative work in this book demonstrates a deep understanding of the subject and a passion for learning. "Theoretical Physics, Volume 4. Relativistic Quantum Theory, Part 1" is not just a textbook, but a real encyclopedia of knowledge that can become the basis for further study of physics. It is suitable for readers seeking a deep understanding of the laws of nature, as well as for those who want to expand their horizons in the field of theoretical physics. This book will become an indispensable assistant for anyone who wants not only to study physics, but also to understand its philosophical and conceptual aspects. Do not miss the opportunity to immerse yourself in the world of relativistic quantum theory with Landau and Lifshitz This book is your key to understanding the complex and exciting phenomena that shape our world.