This contribution to the economic history of the Renaissance in Italy is based upon material in the Selfridge Collection of Medici manuscripts lent to the Graduate School of Business Administration of Harvard University by Mr. H. Gordon Selfridge of London, material never before available to the public. The work is designed to show something of the rich content of the Collection as a whole, covering the closing years of the fifteenth century, a time of great political confusion and of economic depression, and including bills of exchange, articles of association, correspondence between Florentine merchants and their agents who were located in Pera (a suburb of Constantinople), and also a glossary of business and historical terms found in the manuscripts, illustrations of certain pages, and a biographical appendix.