INTOR is an international cooperatative project which started already in 1979. Its task is the demonstration of Tokamak reactor physics and to serve as a test bed for the development of fusion reactor technology. The development of the INTOR concept has reached a rather high degree of self-consistency. The concept is rather conservative in order to achieve sufficient predictability of performance. Particular discussion is devoted to the status of the INTOR physics data base and on the strategy of their generation. It is concluded that INTOR offers a chance to go to the next step within a reasonable time during which the data base will still be improved. The INTOR design concept is also very useful as a reference system for assessing the impact of innovative concepts.