He directed two expeditions, the Caribbean Motion Picture Expedition, a two-and-a-half month, 5,000-mile voyage aboard the four-masted schooner, Doris Hamlin, and the West Indies Mineralogical Expedition, which completed the first mineralogical survey of the island of Puerto Rico under US rule. Upon his return to the United States, and with scientific grants few and far between, he began to write his way to fame and fortune, supporting his research by becoming one of the most popular writers of the 1930s.
As the editor of Thrilling Adventures Magazine, one of the more than 30 magazines he headlined, wrote in October 1934, "L. Ron Hubbard needs no introduction. From the letters you send in, his yarns are among the most popular we have published. Several of you have wondered, too, how he gets the splendid color which always characterizes his stories of the faraway places. The answer is: Hes been there, brothers. Hes been and seen and done. And plenty of all three."
While continuing to write for his New York editors as well as screenplays for Hollywood such as Secret of Treasure Island, he never stopped his vital researches into man.