This study is all about the evolution of inductive output tube (IOT) and its significance in the current scenario. The historical review with timeline is briefly discussed. The basic design considerations and operating principle of IOT have been described. This tube is opted for many applications these days over other conventional vacuum tubes for various advantages. Initially used for television transmitters, this tube is now well recognized for other industrial applications also which are discussed in the study. A comparative review of IOT over other conventional tubes is also given wherever required. The current state of the art of the tube is described to convey the present needs of the device.