The book “Testing of electric DC machines” by Sergey Alexandrovich Nikolaev is a unique work that will become a reference book for students, engineers and everyone interested in electrical engineering and mechanical engineering. In this edition, the author shares not only the theoretical foundations, but also the practical aspects of testing electric machines, which makes it an indispensable source of knowledge for professionals and amateurs. Sergei Nikolaev, known for his deep knowledge in the field of electrical engineering, in his book touches on key topics relating to the testing of electric DC machines. It explains how to conduct tests correctly, what methods and technologies to use, and what parameters need to be taken into account to achieve accurate and reliable results. The book covers a wide range of issues, ranging from the basics of electric machines and ending with complex methods of diagnosis and analysis of their condition. Who is this book intended for? First of all, it will be useful for students of technical universities studying electrical engineering and mechanical engineering . It will also interest graduate students and young professionals seeking to deepen their knowledge in the field of testing and diagnostics of electrical machines. Engineers and practitioners working in the field of energy and electrical engineering will find in it many useful tips and recommendations that will help in their daily work. The book will be interesting to those who are just interested in electrical engineering and want to expand their horizons. One of the key topics raised in the book is the importance of testing to ensure the reliability and safety of electrical machines. The author explains in detail what tests need to be carried out at various stages of operation of machines in order to prevent possible breakdowns and accidents. It also considers the impact of various factors on the operation of machines, such as temperature, load and operating conditions. These aspects make the book especially relevant in the light of modern requirements for the quality and reliability of electrical equipment. The style of Sergey Nikolaev is distinguished by clarity and accessibility, which allows the reader to easily assimilate complex technical concepts. His approach to the presentation of the material is based on a combination of theory and practice, which makes the book not only a textbook, but also a practical guide. Nikolaev is also known for his other work in the field of electrical engineering, and his experience and knowledge make this book a valuable contribution to the literature on this topic. If you are looking for a book that will help you understand the tests of electric DC machines, “Testing of electric DC machines” will become your reliable assistant. It will not only expand your knowledge, but also inspire new ideas and projects in the field of electrical engineering. Readers interested in topics related to mechanical engineering, electrical engineering, as well as testing and diagnostics of equipment, will find in this book a lot of useful and relevant information. Do not miss the opportunity to immerse yourself in the world of electric machines and tests, discovering new horizons of knowledge and practical skills. The book of Sergei Nikolaev is not just a textbook, but a real guide to the complex but fascinating world of electrical engineering.