Dungeons and Dragons was made by two people: Ernest Gary Gygax and David Arneson. Gygax founded a company, Tactical Studies Rules, just to formally publish D&D and have more people enjoy it. Until 1997, his company owned the rights to D&D. They also made updates and new rules. You could say that Wizards of the Coast makes the new D&D now, though. They bought Tactical Studies Rules when it was going bankrupt. Until this day, they have been making new changes to make the game more fun and enjoyable.