 Most of his non-fiction work focused on two subjects — the circus and crime.He was Annie Oakley's first biographer.His books "Here's to Crime" (1937), "Ten-Thousand Public Enemies" (1935) and "Designs in Scarlet" (1939) championed the cause of the young Federal Bureau of Investigation and made the case that corrupt local governments and police forces permitted lawlessness to flourish in many parts of the United States.