The latest technique for critical machines - Steam turbines is "Condition based Maintenance (CBMS)" in which the machine is continuously monitored for its health. Any deteriorating trend in monitored parameter of machine gives an alarm to maintenance personnel who can then plan and schedule the maintenance activity optimally, avoiding accidental hazards due to sudden breakdown, minimizing maintenance cost and downtime. This Book incorporates a case study of GHTP Thermal Power Plant in an attempt to find the problems with planned and breakdown maintenance practiced at the plant and to find the scope for CBMS to increase availability of plant.