The book "Technical and economic substantiation of engineering solutions in diploma projects on reliability, repair and operation of machines" by Novikov Alexander Nikolaevich, Batishchev A. N. and Kuznetsova Yu . A. is a unique teaching aid that will become an indispensable assistant for students and specialists in the field of mechanical engineering, as well as for anyone interested in the reliability and operation of machines In this edition, the authors have gathered a wealth of experience and knowledge that will help readers to understand more deeply how to properly justify engineering solutions in graduate projects. The book covers a wide range of topics, ranging from the basics of feasibility studies to the practical aspects of repair and operation of machines. The authors consider key aspects such as reliability analysis, selection of optimal solutions and cost-effectiveness assessment. Each chapter is filled with examples that will help readers in practice to apply the knowledge gained . This makes the book not only a theoretical manual, but also a practical guide for future engineers. Who can like this edition? First of all, it is addressed to students of technical universities, students at the faculties of mechanical engineering, as well as graduate students and young professionals who are just starting their way in this field . In addition, the book will be useful to teachers engaged in the preparation of future engineers, and practicing engineers who want to update their knowledge and skills in the field of feasibility studies .. The topics raised in the book are relevant and important in today's world, where the efficiency and reliability of machines play a key role in production processes. The authors emphasize the need for an integrated approach to the design and operation of machines, which allows not only to increase their reliability, but also significantly reduce maintenance and repair costs. This is especially important in the face of fierce competition in a market where every detail matters. The style of the authors is distinguished by the clarity and accessibility of the presentation, which makes the material understandable even for those who are just beginning to get acquainted with this topic. Novikov, Batishchev and Kuznetsov are experienced specialists who not only have deep knowledge in their field, but also know how to convey them to the reader. Their previous work is also noteworthy, as they have already established themselves as authors of quality and useful teaching aids. The book "Technical and economic justification of engineering solutions in diploma projects on reliability, repair and operation of machines" is not just a textbook, but a real guide to the complex but fascinating world of engineering. It will help readers not only to master the necessary knowledge, but also teach them to think critically, make informed decisions and develop effective projects. If you are looking for a book that will help you understand the intricacies of the feasibility study and give practical skills for successful work in the field of mechanical engineering, then this publication will become your reliable companion. Do not miss the opportunity to enrich your knowledge and prepare for a successful career in engineering!