Added by 8of5

Landru was a mind controlling computer on the planet Beta III. (TOS episode: "The Return of the Archons",TOS novel: The Rift) It was given the same name as its creator, who programmed the machine with an approximation of his personality and philosophy. The machine Landru served as the guiding force for the planet's population for centuries, allowing all to work solely for the good of the many rather than for the self, (with the exception being the annual 'Festival' where in celebration the younger population's Ids were for one night allowed to run wild without restraint).

A number of Starfleet Crew on an observation mission, followed by Sulu and another crew member in a follow up mission, were forcefully joined into The Body being mistaken for deviants. Captain Kirk sought to retrieve his lost crew eventually uncovering the truth of the planet's 'leader.' Apparently unable to free his crew mates any other way, Captain Kirk readily (perhaps too eagerly) ignored the Prime Directive and forcefully told the computer that it self was a threat to The Body and that it had failed to exploit the full potential of every individual member of society. Horrified at this contradiction, and suffering a nervous breakdown, the computer cried out in desperation for guidance from its long dead creator - and perished.

Landru article at Memory Alpha, the wiki for canon Star Trek.