He was an engineer who had a hard time getting his idea listened to.
I hate it when people split hairs, but I've got to be that guy today. LOR wasn't John Houbolt's idea, although he was most definitely one of the few that believed in it early on. He was responsible for getting the powers that be to consider it sooner than later but he didn't come up with it himself. He merely recognized a good idea when he saw it, and made sure other people saw it too.