The book describes the importance of the maintenance, triggers and key performance indicators in practice. The lean tools contain the most popular tools and methods for modern maintenance teams and engineers. The key performance indicators, such as OEE (Overall Equipments Effectiveness) and the method of root cause analysis help maintenance team to solve different technical or maintenance problems in the daily routine. The modern lean manufacturing principles increased the importance of maintenance and operation. The book contains 25 chapters and several sub-chapters. The chapter before the last contains different case studies from industrial field, these case studies come from the following areas: 5S, TPM and FMEA (Failure Mode and Effect Analysis). These case studies can be help to the engineers of the future to implement and improve their skills and methods in the practice. The book will give guidance on the possibilities of new maintenance methods, which are based on lean techniques and philosophy. The main purpose of this book on Maintenance Engineering is to introduce the main definitions and tools for the international trends and brands. I hope students and engineers will use this book with satisfaction during their study or work.