TRADERS...And constantly in advance of the political hegemony of the Foundation were the Traders, reaching out tenuous fingerholds through the tremendous distances of the Periphery. Months of years might pass between landings on Terminus; their ships were often nothing more than patchquilts of home-made repairs and improvisations; their honesty was none of the highest; their daring ... Through it all they forged an empire more enduring than the pseudo-religious despotism of the Four Kingdoms. With Psycohistoric inevitability, economic control of the Foundation grew. The traders grew rich; and with riches came power. Tales without end are told of these massive, lonely figures who bore half-seriously, half mockingly a motto adopted from one of Salvor Hardin's epigrams, "never let your sense of morals prevent you from doing what is right!" It is difficult now to tell which tales are real and which apocryphal. There are none probably that have not suffered some exaggeration... It is sometimes forgotten that Hober Mallow began life as an ordinary trader. It is never forgotten that he ended it as the first of the Merchant princes. ...
Traders are a small group of people, either natives to the First Foundation, or later natives of the planets that fell under the control of the First Foundation. They are merchants who, armed with the best vessels the Foundation could provide, explore the depths of space to find territory where they can sell their wares. They are important in the sense that they are instrumental in spreading the hegemony and power of Terminus in The Periphery after the collapse of the Galactic Empire.