While the great mining bonanzas of the nineteenth-century West made eastern California and Nevada the subject of legend, much of the wealth from the mines flowed to San Francisco and made possible the growth of the city and some fabulous personal fortunes. Among the wealthiest and most powerful of the Bonanza Kings was William Bowers Bourn I and his son and successor, William Bowers Bourn II. The elder Bourn, descendant of an early New England family,...