Hobo Symbols From The Great Depression: The Secret Language Of America’s Itinerant Workers In 1972 American industrial designer Henry Dreyfuss (March 2, 1904 – October 5, 1972) published The Symbol Sourcebook, A Comprehensive Guide to International Graphic Symbols. “A ready reference aid and an inspiration to designers . All in all the best book now available on symbols.” –Library Journal. This visual database of over 20,000 symbols provided a standard for industrial designers around the world. He included a section of 60 hobo signs, used by ‘transient working class men and women who traveled by train to communicate with one another in the Great Depression, late nineteenth and early twentieth century.