The book “Group Theory and Its Applications to Quantum-Mechanical Theory of Atomic Spectra” by Eugene Wigner is an outstanding work that combines deep mathematical concepts and physical ideas, opening the world of quantum mechanics to the reader through the prism of group theory. Wigner, a Nobel laureate, is not only an outstanding physicist, but also a remarkable popularizer of science, which makes his work accessible and interesting to a wide audience. In this book, the author explores how the mathematical structure of group theory can be applied to understand atomic spectra, which is a key aspect of quantum mechanics. Wigner begins with the foundations of group theory, gradually delving into more complex concepts and showing how they can be used to describe symmetries in quantum systems. The reader will be able to see how these abstract mathematical ideas find their application in real physical phenomena, such as spectra of atoms and molecules. This book will be of particular interest to students and graduate students studying physics and mathematics, as well as researchers working in the field of theoretical physics. It is suitable both for those who are just beginning their journey in quantum mechanics, and for more experienced readers who want to deepen their knowledge of symmetries and their role in physics. The book can also attract the attention of mathematicians interested in the applications of group theory in the natural sciences. The topics raised in the book cover a wide range of issues, including symmetries, transformation groups, and their physical interpretations. Wigner masterfully shows how understanding these concepts can lead to a deeper understanding of quantum processes. He emphasizes the importance of symmetries in physics, which makes this work not only scientific, but also philosophical, forcing the reader to think about the nature of reality. Wigner's style is clear and logical, which makes complex topics more easily understood. His ability to explain even the most abstract ideas in simple and understandable language is one of the reasons why his work remains relevant and in demand. Wigner is also known for his other works, such as Quantum Mechanics and its Applications, where he continues to explore topics related to quantum theory and mathematics. “Group theory and its applications to quantum mechanical theory of atomic spectra” is not just a textbook, but a real find for anyone who seeks to understand how mathematics and physics are intertwined in the study of the microworld. The book offers the reader a unique opportunity to see how abstract mathematical constructs can explain real physical phenomena, making it an indispensable tool for students and researchers. If you are interested in topics such as quantum mechanics, atomic spectra, symmetry in physics or group theory, then this book will be a real treasure for you. It will not only enrich your knowledge, but also inspire further research in physics and mathematics. Do not miss the opportunity to immerse yourself in a world where mathematics and physics merge, opening up new horizons of understanding our Universe.