This course provides the participants with a complete and up-to-date overview of the technology of boiler operations and maintenance. It reviews boiler types, combustion fundamentals, boiler fuels, and burners. Boiler efficient operations and maintenance are then covered. Increasing the life of the boilers, best performance, and safe and economic operation with least pollution to the environment are the target and consequence of proper operation and correct control. Best practices of boilers operations and maintenance that achieve these targets are then discussed with some case studies.