Mr. Donner took over the family-owned grain mill while still in his twenties. In relatively short order, he restored to profitability what had previously been a failing enterprise. Before he was 30, Mr. Donner foresaw that the then recent discovery of natural gas deposits in Indiana would inevitably attract new industries to the area. He invested promptly--and with conspicuous success--in real estate. By the time he was 30, he had launched the National Tin Plate Company of North Anderson, Indiana; three years later, having patented an ingenious rolling process for tin plate manufacture, he constructed another plant in Monessen, Pennsylvania. Eventually, he sold all his tin plate interest to the American Tin Plate Company. Mr. Donner's next venture was in steel products. With the Mellon brothers and Henry Clay Frick, he founded a rod, wire, and nail enterprise, known as the Union Steel Company, of which he was President. Union Steel was based in Donora, Pennsylvania, a town whose name derives from those of Mr. Donner and Nora Mellon. The company was merged with the Sharon Steel Company in 1902, and was purchased in 1903 by the United States Steel Corporation. Mr. Donner later became President of Cambria Steel Company and then Chairman of the Board of the Pennsylvania Steel Company. His final business undertaking involved the purchase of assets which formed the Donner Steel Company of Buffalo, New York, an enterprise he operated successfully until selling his interest in 1929. In that year a merger of Donner Steel, Republic Iron and Steel, and two other independent steel companies was arranged by Cyrus Eaton. After losing his son, Joseph, to cancer in 1929, Mr. Donner turned his formidable energies to the then infant field of cancer research. He established the International Cancer Research Foundation in 1932 to honor his son's memory. In 1961, The William H. Donner Foundation was incorporated with the endowment originally established by Mr. Donner for the International Cancer Research Foundation. William H. Donner died in Montreal in 1953.