The concept of revenue management (RM) has been used widely in the air-transportation industry, and proven as a good system for managing perishable assets. While the airlines are the oldest and most sophisticated users of RM, these practices have been an enormously important innovation in other service industries such as the travel, the railway, the internet and the manufacturing industries. In this paper, reviewing several studies on RM, we introduce the fundamental concepts and the major models of RM covering seat allocation with multiple fare classes and overbooking. Future research directions also are suggested.