John (John Harmon) Mason

John Harmon Mason was an American writer identified in library and public-domain records as born in 1867 and associated with the freethought tradition. Surviving catalog records connect him most clearly with Evolution Made Plain, a short popular science work published in 1923 by the Haldeman-Julius Company.

That book presents evolution in concise, accessible terms, suggesting he wrote for readers outside academic circles and wanted scientific ideas to be easy to grasp. Public-domain sources such as Wikisource and Project Gutenberg preserve his work today, which has helped keep his name alive even though detailed biographical information appears to be scarce.

Because reliable source material on his personal life is limited, much of Mason's story has to be told through his writing rather than through a full documented life history. What can be said with confidence is that he contributed to the early twentieth-century tradition of affordable, plainspoken educational publishing.