John Houbolt was a NASA engineer who is credited with persuading NASA to adopt the Lunar Orbit Rendezvous (LOR) method to get man to safely land on the moon and return home.
To add some perspective here at the time that he championed the method NASA knew that their goal was to go to the moon, a large launch vehicle was well into its design stage but that was about it. NASA had yet to dock two vehicles in space, they had not designed, built, or tested any of the hardware, software and techniques to carry out the job.
There were two alternative methods that were prevalent at the time, and they were both being championed by such luminaries as Werner Von Braun, and may of NASA's leading engineers.
Houbolt realised that these were impractical and went on a one man crusade to convince his peers that his proposal was the best chance that NASA had of achieving their goal. He was derided in some quarters, and dismissed by others. Finally in desperation he leapfrogged his immediate superiors and wrote a letter to the top official in NASA putting his case forward.. Robert Seamans who was the administrator was sufficiently convinced that he instructed his subordinates to seriously consider the matter. Eventually there was a mood swing, Von Braun and many others were brought around to his proposal, and it was adopted.