In December 1919, Ambrose Small, the mercurial owner of the Grand Opera House in Toronto, closed a deal to sell his network of Ontario theatres, deposited a million-dollar cheque in his bank account, and was never seen again. As weeks turned to years, the disappearance became the most "extraordinary unsolved mystery" of its time. Everything about the sensational case would be called into question in the decades to come, including the motivations of his inner circle, his enemies, and the police who followed the trail across the continent, looking for answers in asylums, theatres, and the Pacific Northwest. In The Missing Millionaire, Katie Daubs tells the story of the Small mystery, weaving together a gripping narrative with the social and cultural history of a city undergoing immense change. Daubs examines the characters who were connected to the case as the century carried on: Ambrose's religious wife, Theresa; his long-time secretary, Jack Doughty; his two unmarried sisters, Florence and Gertrude; Patrick Sullivan, a lawless ex-policeman; and Austin Mitchell, an overwhelmed detective.