Study of the grand ideas in economics has a perpetual intellectual fascination in it's own right. It can also have practical relevance, as the global economic downturn that began in 2007 reminds us. For several decades, the economics establishment had been dismissive of Keynesianism, arguing that the world had moved beyond the "depression economics" with which it dealt. Keynesian economics, however, has now staged a comeback as governments attempt to formulate policy responses to the Great Recession of the first decade of the twenty-first century. Study of the grand ideas in economics has a perpetual intellectual fascination in it's own right. It can also have practical relevance, as the global economic downturn that began in 2007 reminds us. For several decades, the economics establishment had been dismissive of Keynesianism, arguing that the world had moved beyond the "depression economics" with which it dealt. Keynesian economics, however, has now staged a comeback as governments attempt to formulate policy responses to the Great Recession of the first decade of the twenty-first century.