This work presents an outline of the history of scientists and the city where the world’s first relativistic CRM device, known today as a Gyrotron, was created. CRM can be explained as “a microwave source of stimulated radiation based on the cyclotron resonance phenomenon.”. The story begins in 1898 with the establishment of the Emperor Nicolas II Warsaw Polytechnic Institute and ends in 1964 with the launch of the world’s first Gyrotron at the Nizhegorodsky Polytechnical Institute (later Gorky). The principle of gyrotron operation is very briefly presented in the paper, but mainly, according to the idea of this work, a lot of space is devoted to people, scientists and organizers of science in Gorky, the first who created this device, and therefore the work is limited to presenting the events related to the creation of the Gyrotron in 1959‒1967.