The exceptional collections of the Food and Agriculture Organization (FAO) David Lubin Memorial Library are based on an original core collection of almost 400,000 books in agriculture, fisheries, forestry, food and nutrition, rural development and related topics from the International Institute of Agriculture (IIA). This paper examines the evolution of the IIA, its collections, its founder David Lubin, mediator extraordinaire and David Lubin's correspondence with his contemporaries, including H.G. Wells. The IIA was one of many ideas originating with David Lubin, a selfeducated Polish-born American, who in the course of his career had worked as a jeweler, oil-lamp salesman, gold prospector, department store owner and manager and farmer. Finding that normal business practices resulted in financial losses from wheat and fruit farming in California, Lubin quickly realized the uncertainty was caused by the farmer's lack of access to current national and international agricultural information. The story of the evolution of the IIA is largely a record of David Lubin mediating continuously, in person, by letter and through newspaper articles. Lubin established information exchange agreements directly with ministers of government and worldwide farm organizations; at his own expense he distributed thousands of documents and worked without monetary recompense until his death in 1919. The leadership and energy of David Lubin were emulated by IIA staff until its dissolution in 1946. They leave the lasting tribute of a precious historic collection spanning over four centuries. When FAO was moved to Rome in 1952, the Government of Italy formally granted to FAO the custodianship of this great heritage.