The book “Ordinary Differential Equations” by Lev Pontryagin is an outstanding work that has become a classic in the field of mathematical analysis and the theory of differential equations. Pontryagin, a well-known Russian mathematician, left a significant mark in various fields of mathematics, and his work on differential equations was no exception. This book is not only a textbook, but also an in-depth study that opens the reader many opportunities for understanding complex mathematical concepts. In "Ordinary Differential Equations" Pontryagin considers the basic principles and methods of solving differential equations, which are the most important tools in mathematics and applications in physics, engineering and other sciences. The author skillfully combines theory and practice, providing readers with not only formulas and algorithms, but also an intuitive understanding of the processes behind them. The book covers a wide range of topics, including linear and nonlinear equations, systems of equations, and methods of qualitative analysis of solutions. This edition will be of particular interest to undergraduate and graduate students studying mathematics, physics, and engineering disciplines. It will also be useful to practitioners who face challenges that require a thorough understanding of differential equations. If you are passionate about mathematics and want to expand your knowledge, this book will become a reliable companion in your learning. The topics raised in the book range from the fundamentals of theory to more complex aspects, such as the sustainability of solutions and the application of methods to real-world problems. Pontryagin not only explains how to solve equations, but also immerses the reader in the world of mathematical thinking, where each equation is not just a set of symbols, but a reflection of real processes and phenomena. This makes the book especially valuable for those who want not only to master the skills of solving equations, but also to understand how these skills are applied in real life. Pontryagin's style is clear and logical, which makes his work available to a wide audience. He skillfully uses examples and illustrations to illustrate complex concepts, which is especially important for readers who may have difficulty perceiving abstract mathematical ideas. Pontryagin is also known for his other works, such as "