He was a science editor who wrote on futuristic subjects , especially pertaining to human space travel .
Harold Horton Sheldon ( April 13 , 1893 -- December 23 , 1964 ) was a Canadian - American physicist , scientist , inventor , teacher , editor and author .
Harold Horton Sheldon was a physicist   who wrote on futuristic subjects , especially pertaining to human space travel .
Harold Horton Sheldon ( April 13 , 1893 -- December 23 , 1964 ) was a Canadian - American physicist , scientist , inventor , teacher , editor and author .