During the first two decades of this century, Sir William Mackenzie was one of Canada's best-known entrepreneurs. He spearheaded some of the largest and most technologically advanced projects undertaken in Canada during his lifetime--building enterprises that became the foundations for such major institutions as Canadian National Railways, Brascan, and the Toronto Transit Commission. He built a business empire that stretched from Montreal to British Columbia and to Riod de Janeiro and Sao Paulo. It included gas, electric, telephone, and transit utilities, railroads, hotels, and steamshs, as well as substantial coal mining, whaling and timber interests. Along the way, he funded the first full-length documentary movie, received a knighthood from George V, and owned Canada's largest newspaper, La Presse. He accumulated an enormous personal fortune, but when he died in 1923 his estate was virtually bankrupt as a result of the dramatic collapse of his Canadian Northern Railway during the First World War.In an era when the entrepreneur has come to be seen as a media hero and when struggles about the role of state enterprise in the transportation and energy sectors consume public policy debate, it is ironic that Mackenzie is largely forgotten by all but a few historians and railway aficionados. He left no papers to guide biographers. After a decade of gathering and piecing together fragments from an immense array of sources, Rae Fleming has written the first biography of the man that the German press extolled as the 'Railway King of Canada.