August Derleth
There are many people who know who August Derleth was - particularly his many fans. And there are many people who do not know who August Delereth was - particularly people who aren't up on early to mid-20th century American popular literature.
But August was not just one of the most prolific writers of the 20th century. His business endeavors also contributed to the development of American culture - a development of which you can learn a bit about if you just click here.