The Book of Mathematics . At 4 p.m.. H. 3. Multiple integrals and their applications. Curvilinear integrals, surface integrals and their applications" by H. A. Kondratieff is a fascinating and deep dive into the world of multidimensional analysis. This is the third part of an extensive tutorial that covers important aspects of mathematical analysis, and will certainly become an indispensable assistant for students, graduate students and anyone seeking to expand their knowledge in the field of higher mathematics. In this book, the author examines in detail multiple integrals, their properties and methods of calculation, as well as their practical application in various fields of science and technology. Kondratiev, known for his clear and accessible style of presentation, makes complex concepts understandable even for those who are just beginning to get acquainted with mathematical analysis. He not only expounds the theory, but also shows how to apply the knowledge gained in practice, which makes this book especially valuable for students of engineering and natural science specialties. The book will be of interest to a wide range of readers: from students and teachers to professionals working in the field of physics, engineering and economics. If you are looking for a tutorial that will help you master topics such as curvilinear integrals and surface integrals, then this publication will be a real find for you. It is suitable for both self-study and as a supplement to coursework. The topics raised in the book cover not only theoretical aspects, but also practical problems, which allows the reader to see how mathematics is applied in real-life situations. For example, Kondratiev explains how multiple integrals are used to calculate the volume of bodies and the area of figures, as well as to solve physics problems related to fields and flows. This makes the book relevant and useful for those who want to see how abstract mathematical concepts find their application in the real world. Kondratiev's style is distinguished by clarity and logic. He skillfully combines theory with practical examples, which makes the learning process not only effective, but also fascinating. In the previous parts of his textbook, the author has already established himself as a master of explaining complex things in simple language, and in this book he continues this tradition. His approach to learning is based on the fact that understanding the basics is the key to successfully mastering more complex topics. If you are interested in mathematics and want to deepen your knowledge in the field of integral calculus, then "Mathematics. At 4 p.m.. H. 3" will be an important step for you on the way to mastery. The book will not only enrich your knowledge, but also inspire you to further study mathematics, opening up new horizons for you. In addition to this, this edition can be useful for preparing for exams and test papers, as it contains many examples and tasks for independent decision. This book will be a reliable companion for all who seek a deep understanding of mathematical concepts and their practical application. Do not miss the opportunity to get acquainted with the work of N. A. Kondratieff and discover new horizons in the world of mathematics!