This chapter introduces J.P. Morgan & Co. and its partners, surveying the history of the bank from its founding. Having done so, the chapter analyzes the businesses J.P. Morgan & Co. conducted under the leadership of Jack Morgan between 1913 and 1929. It argues that the firm was a conservative banking house, selective in its lending, catering to wealthy investors, a roster of major corporations, and foreign governments. Unlike many competitors, the bank issued only bonds before 1929, never floating a stock issue. On the eve of 1929 the bank was flourishing, conservative in its outlook, profitable in its business. The internal organization of the bank is discussed as a bridge to the partners, who ran the bank. Particular attention is paid to the experience, outlook, and views of the senior partners – Jack Morgan, Thomas W. Lamont, Russell C. Leffingwell, and George Whitney. Brief biographies of each illuminate their role in the bank, their world view – politically, economically, diplomatically – arguing that the partnership functioned as a collective helmed by Jack Morgan.