Paul Dettmann has always been interested in true crime. He revived his interest during the year of lockdown, getting hooked on Michelle McNamara's hunt for the Golden State Killer. He was inspired to start the blog, Crime Guy, to document some of the cases that affected him as a child, and other more recent unsolved cases. The success of Peaky Blinders inspired him to look into the lives of British gangsters from the early twentieth century. This is his first book of nonfiction.