The Canadian oil industry had its birth in the early 1850s with Charles Tripp’s early exploration of the “gum beds” in Lambton County. The small urban areas of Canada West were a logical choice for refineries, and London East emerged as a refining centre in the 1860s. Cobban suggests that the growth of petroleum manufacturing here was not stimulated by any direct municipal action, but rather by the presence of a municipal boundary, which prevented the city from imposing regulations on the industry. This resulted in “industrial suburbanization” whereby land-use policies and zoning laws were used to restrict the location of oil refineries to the outskirts of the city. The refining industry shifted from London East to Petrolia following the opening of the town’s second railway in 1878. The Sarnia, Chatham & Erie Railway posed direct competition to the monopoly over freight rates previously enjoyed by the Great Western Railway. Cobban suggests that of the three municipalities, local government actions positively influenced the industry in the case of Petrolia. Direct municipal action in the form of a railway allowed the monopoly over the industry’s transportation to be overcome, leading to the concentration of petroleum manufacturing there in the last two decades of the nineteenth century. When the Standard Oil Company acquired the assets of Imperial Oil in July 1898, company offices were transferred to Sarnia, and Sarnia emerged as the centre of petroleum manufacturing in Canada. Ontario’s system of municipal aid grew out of state involvement in railway promotion, but by 1922 the reforms of the Mowat government had reduced the scale of direct municipal investment in industry. By the 1930s, after two decades of growth, petroleum manufacturing in Sarnia had slipped into a state of relative decline. Wartime rubber shortages resulted in the construction of a synthetic rubber plant in Sarnia, Polymer, a crown corporation. Although the demands on local infrastructure were considerable, Polymer was essentially a federal government operation. Cobban suggests that the story of the making of Canada’s Chemical Valley in Sarnia after the war was mostly a federal one as well. While Cobban sets out to explain the influence of municipal government on the location and development of the petroleum industry in southwestern Ontario, he concludes that it was in the protective trade policies of the federal government where most of the investment in the petroleum industry occurred. In this regard, Cobban suggests, the petroleum industry fits the scholarly narrative about the rise of modern industrial capitalism and the decline of the relevance of municipal corporations. He is careful to point out, however, that municipalities played a role at a critical juncture, accommodating the need for land, tax concessions, and implementing land-use policies. Cobban uses a rich variety of primary sources to build his argument including the business papers and government documents from the three levels of government. A wide array of business papers ranging from the Great Western Railway, to the diaries of J.H. Fairbank of Petrolia, and Polymer Corporation add depth to the study.