Mechanical engineering is one of the oldest and most fundamental branch of engineering that deals with the design, analysis, and manufacture of mechanical systems. It has been a crucial part of human civilization, driving innovation and technological advancements throughout history. Mechanical engineering has been crucial in creating the modern world, from the invention of the wheel to the building of skyscrapers and aeroplanes. Basic Mechanical Engineering is a compulsory paper for first year engineering students. This book is designed to provide an introduction to the fundamentals of mechanical engineering. It is intended for students who are new to the field of mechanical engineering, as well as for those who are interested in refreshing their knowledge of the subject. It broadly covers the basic concepts and applications of thermal engineering, power transmission, manufacturing processes, and material science. Each chapter is structured to provide a clear understanding of the underlying principles and their applications in real-world engineering problems. This book is suitable for students in basic mechanical engineering course and can also be used as a reference for practicing engineers and professionals looking to refresh their knowledge of fundamental mechanical engineering concepts. The author made an effort to cover the most syllabi from all of the main Indian institutes and universities in this book. I hope that readers find this book informative and engaging and that it inspires them to pursue further studies in mechanical engineering. With a solid understanding of the principles covered in this book, readers will be well-equipped to tackle a wide range of mechanical engineering problems and applications.