City of Gangs draws on research conducted at the Mitchell Library in Glasgow, the National Archives of Scotland (now National Records of Scotland) in Edinburgh and the British Library Newspaper Library at Colindale, North London. When I made my first visit to Glasgow in the autumn of 1995, my starting point was the series of annual indexes to the Glasgow Herald. These contained lists of every criminal trial covered by the Herald during the 1920s and 1930s. The Herald‘s reports led me into the world of the Billy Boys, the San Toy, the Kent Star and the Beehive Boys. I soon became familiar with their leading figures, men like Billy Fullerton, the Mullen brothers and Andrew Mulvey, whose notoriety lasted well beyond their own lifetimes. In the years since, I’ve followed them – in what felt like a long-running, historical detective pursuit – through the pages of newspapers, through the registers of Glasgow Sheriff Court and Barlinnie prison, through the manuscript records of High Court trials and inquiries into prison disturbances, into parish relief case-files, and finally, into the registers of births, marriages and deaths held by the Scotland’s People website. City of Gangs is my attempt to make sense of their lives and times, as well as their crimes.