Finance departments have often been portrayed as guardians of the public purse. In The Guardian, a multidisciplinary group of contributors examines the Ministry of Finance of Ontario since the Second World War. During the last sixty years the Ministry was transformed from a relatively small "Treasury" to a sophisticated policy machine. What started as a modest bookkeeping operation evolved into a key bureaucratic and policy agency as the government of Ontario assumed a leadership position in developing the province. These essays reveal Ontario"s "finance" as a dynamic policy issue shaped by the personalities of premiers and ministers, the energies of public servants at all levels, and a critical dialogue between political and administrative worlds. Drawing on different methodologies, this collection profiles a ministry as policy entrepreneur, spender, revenue generator, capacity builder, budget director, program manager, and intergovernmental agent. The Guardian fills a significant gap in public administration literature and in so doing describes how Ontario"s Ministry of Finance defined its role as "guardian."