The thesis provides an account of the development and the eventual elimination of the illegal horserace gambling market. Prior to the introduction of totalisators in 1870 bookmakers (bookies) provided the only option for legal on-course horserace gambling. Using an Actor-Network approach (Latour 1986) I track the transformations of totalisators across times and places to provide a historical account of the development and the co-existence of both legal and illegal horserace gambling markets, documenting the 100 year struggle by racing clubs and successive Governments to remove illegal bookmakers from horserace gambling markets. My argument is that the illegal gambling market survived for as long as it did because bookmakers' constructed extensive actor-networks that enabled them to provide a faster and more accessible betting service to punters. A significant feature in their survival was also the public and police tolerance of their presence. I argue that no one actually 'kills the bookies'. At each stage in the transformation of the scale and operation of totalisators, punters gradually began to use the services provided by a legal market. I document how the drift of legislation, coupled with technological changes and the establishment of new legal gambling sites, led to the expansion of global legal gambling markets that included sport bookmakers and legal horse racing bookmakers. These developments, especially computerisation, enabled the legal market to expand and reconfigure networks providing flexible, real and online access points for betting. These developments ultimately eliminate the comparative advantages of the local illegal bookmakers and bring to an end the illegal horserace gambling market.