Jay Cooke was a leader in the transformation of the earlier type of passive banker into a promoter and director of enterprise. To meet the unprecedented needs of the Federal government during the Civil War, he brought a great organization and high pressure selling into the securities business. In the railroad boom following the war, he transferred his organization and methods to the support and promotion of railroads. As banker-promoter, he pointed the way towards the methods which became the basis for the powerful investment-banker type. Henrietta Larson’s book emphasizes his business career rather more than the personal and public aspects of his life. In contrast to many business biographies, it is written solely to give as accurate a picture as possible of the workings of an important section of American business and to study the career of one important banker carefully and impartially.