It was probably at the Arctic Red River (where on July 20, 1906, I first saw an Eskimo) that I first heard of Captain Leavitt, who, I found later, was known on the lower Mackenzie, as well as on the shores of the western Canadian Arctic, as “the man who started the search for cancer.” Or perhaps I first heard of Leavitt the next day, July 21, at Fort McPherson, where I met John Firth, Hudson's Bay Company factor, destined to be my friend until his death two decades later. In later years we talked a great deal of Leavitt, whom Firth admired, and whose search for cancer in northeastern Siberia, the Aleutian Islands, Alaska, and northwestern Canada, led a half century later to the writing of this book.