American financier and railroad builder Jay Gould (1836-1892) began as an unprincipled stock manipulator and became one of the most acute businessmen in America's age of industrial capitalism. He operated in an era when speculative capital could play a constructive role.

Jay Gould, christened Jayson, was born in Roxbury, N.Y., on May 27, 1836, a farmer's son. He obtained some education in a local academy and also learned surveying. Between the ages of 18 and 21 he helped prepare maps of New York's southern counties. By 21, with a stake of $5,000, he and a partner opened a leather tannery in northern Pennsylvania.

Gould then moved to New York City, where he set up as a leather merchant in 1860. Before long, however, he found his forte in Wall Street, ostensibly as a stockbroker but really as a speculator. In that period of unregulated finance Gould quickly mastered the intricacies of corporate management and...