Theoretical Physics, Volume 4. Relativistic Quantum Theory, Part 2" is an outstanding work written by two great scientists of the 20th century, Lev Davidovich Landau and Evgeny Mikhailovich Lifshitz. This volume is part of an extensive course in theoretical physics that has become a classic and the basis for many generations of physicists. If you are interested in physics at a deep level, strive to understand complex concepts and want to expand your knowledge of relativistic quantum theory, then this book will become a real treasure for you. The second part of the fourth volume deals with a number of key aspects of relativistic quantum theory, including particle interaction, quantum electrodynamics, and field theory. The authors masterfully explain complex mathematical concepts, making them available to the reader who already has basic knowledge in physics and mathematics. Each chapter is imbued with a deep understanding of the subject and the desire of the authors to convey their knowledge, which makes reading not only useful, but also fascinating. This book will be of particular interest to students and graduate students of physics, as well as teachers and researchers working in the field of theoretical physics. If you are already familiar with works such as Landau's Course in Theoretical Physics and Lifschitz or Schrdinger's Quantum Mechanics, then you will appreciate the level of depth and rigor that the authors suggest in this volume. The book can also attract the attention of scientists and specialists engaged in modern research in the field of particle physics, astrophysics and other related disciplines. The topics raised in this book cover not only theoretical aspects, but also practical applications of relativistic quantum theory. The authors discuss how these concepts affect our understanding of the universe, the interaction of elementary particles, and even phenomena such as black holes and cosmic radiation. This makes the book not just a textbook, but a real guide to the world of modern scientific discoveries and theories. Landau and Lifschitz’s style is unique: they skillfully combine rigorous mathematical formulation with an intuitive explanation of physical processes. Their approach to learning and explaining complex topics makes this book especially valuable for those who want not only to learn the material, but also to develop critical thinking in the field of physics. Landau, a Nobel laureate, and Lifschitz, known for his contributions to theoretical physics, create an atmosphere in which the reader feels involved in the process of discovering new knowledge. In conclusion, "Theoretical Physics, Volume 4. Relativistic Quantum Theory, Part 2 is not just a book, but a whole world worth diving into for anyone seeking to understand the laws governing our universe. If you are looking for a deep and meaningful reading that challenges your intellect and expands your horizons, this book will be a real discovery for you. Do not miss the opportunity to get acquainted with the work of two outstanding minds who forever changed the face of physics.