Mystery Trivia Tuesday: Who IS this Guy?

Who am I? You mean besides being the Kansas state spelling bee champion and the inventor of a school banking system which helped school children keep track of money they saved? Well, where do I begin? I knocked around for a few years trying on several different jobs, about thirty, I think. I served in the Navy under Teddy Roosevelt. After earning enough royalties from that ingenious bookkeeping invention, I headed for Europe to bum around awhile. When I returned to the U.S., I began writing short stories on a variety of subjects: romance, adventure, science fiction; I even wrote poetry. I went to Paris in 1929 and there I wrote my first book, How Like a God. When I returned to the U.S. the second time, I tried my hand at writing detective fiction and never looked back. Still don't' know who I am? Here's a hint; my middle name was Todhunter.