The "Brother Assassin", written by Fred Saberhagen in 1969, introduced the complete concept for a telepresence master-slave humanoid system. In the novel, the concept is described as follows: "And a moment later it seemed to all his senses that he had been transported from the master down into the body of the slave-unit standing beneath it on the floor. As the control of its movements passed over to him, the slave started gradually to lean to one side, and he moved its foot to maintain balance as naturally as he moved his own. Tilting back his head, he could look up through the slave's eyes to see the master-unit, with himself inside, maintaining the same attitude on its complex suspension."