John Gill Professor John Gill was a Federation historian who lived during the mid - 23rd century . Spock , who studied Earth history from a text prepared by Gill , was impressed by his treatment of history as " " causes and motivations rather than dates and events . " " James T . Kirk , who studied under Gill at Starfleet Academy , remembered him as " " the kindest gentlest man I ever knew . " " ( ) Gill once referred to Earth Starfleet Captain Jonathan Archer as " " the greatest explorer of the 22nd century . " " ( ) In the mid - 2260s , John Gill was stationed on the planet Ekos as a cultural observer . His analysis of the Ekos was that the planet was in a state of anarchy and took it upon himself to use his knowledge of history to help the local people . To this end , he created a version of Nazi Germany on the planet that was focused on social and economic renewal without the racial and / or religious persecution that marked the first Nazi State on Earth . Professor Gill provided much needed structure to the society by giving the local people the Nazis ' richly symbolic culture to build on . In 2268 , Starfleet lost all contact with Gill for several months and dispatched the starship to search for him . When Captain Kirk and Commander Spock beam ed down to Ekos , they were stunned to find a mid - 20th century style Nazi state bent on destroying the neighboring planet , , and all the Zeon s living on Ekos . Kirk and Spock were also shocked to learn that John Gill had somehow become the Führer of Ekos . When Kirk finally managed to locate Gill , the captain found his old history professor in extremely bad health . Apparently , Gill had been drugged by the Deputy Führer , Melakon . After Dr . McCoy administered several injections of a stimulant into Gill ' s body , Spock performed a mind meld on the historian , enabling Gill to answer Kirk ' s questions . Gill claimed that when he had first arrived on Ekos , he had found the planet in such a fragmented and divided state that he decided to break the Prime Directive in order to transform Ekos into a simulation of the most efficient state Earth had ever known . According to Gill , his plan had initially worked until Melakon began to drug him . As Gill ' s attention returned to his current situation , Kirk urged the historian to notify the Ekosians of Melakon ' s betrayal before the " Final Decision " to destroy Zeon began . Gill was able to transmit a message to the Ekosians and tell them to stop the invasion of Zeon . He also apologized to Zeon , insisting that he himself , not the people of Ekos , bore the blame for this aggression . He then denounced Melakon as a traitor , at which point the Deputy Führer grabbed a soldier ' s machine gun and assassinated Gill before he himself was killed by Isak . Before Gill died , he admitted to Kirk he was wrong to violate the Prime Directive . ( ) Appendices . Background information . John Gill was played by David Brian . Apocrypha . In the reference book the " Star Fleet Medical Reference Manual " , an essay titled " Historical Trends in Medicine " by John Gill serves as the introduction . He is listed as holding the academic degree of Doctor of Philosophy ( Ph . D . ) , and it references several historical medical landmark works , such as " The Surgeons Mate " , a real - life Navy guide written in the 17th century , and several from the " Star Trek " universe . Publications by John Gill , e . g . , " Small Steps and Giant Leaps : A History of Humankind in the Galaxy " from 2143 or a multi - volume series about World War III , are also mentioned in the reference book " " .