Fundamental principles and theoretical aspect of turbine operation are presented first to provide a basic knowledge of working principle of turbine; followed by other principal divisions - turbines construction, installation, governing system, lubrication & controls, operation and maintenances for ease of understanding. The book is divided in twelve chapters dealing with basics of turbine, cycles of operation, theory of turbine, construction of turbine, installation, metallurgy of steam turbine, governing system, lubrication and controls, operation, maintenance, condition monitoring by performance, and electrical systems.Author has tried his best to cover all important aspects of various disciplines in power plant to accomplish a single complementing book for engineers working in power plant. The book is formatted as work book, dealing precisely with the help of sketches, tables, graphs and troubleshooting charts to enable readers to use it as practical reference book in their work area. The readers may get acquainted to adopt the standard operating procedures, installation, predictive & predictive maintenance practices to operate STG at full capacity and optimum thermal efficiency. The book familiarizes from erection to commissioning activities and subsequent operation and maintenance of steam turbo-generators and auxiliaries. Some aspects related to STG e.g. DCS, Centrifugal pumps, Cooling Towers are not covered in this book as these parts are described in details in other publications of author.