This series contains the DuPont Company's correspondence with suppliers, attorneys, customers, labor agents, and sales agents. The files document the importation of saltpeter and nitrate for the manufacture of black powder, the selling of gunpowder to the government, and the selling of blasting powder to coal mine operators and railroad contractors. The correspondence also illustrates the process by which Irish workers were recruited with the assistance of Philadelphia agents. There is also some correspondence with competing powder manufacturers and makers of powder machinery. Letters also describe the organization and operation of the Gunpowder Trade Association between 1872 and 1901.

About half of the letters in the series represents correspondence with the company's 360 sales agents. These agents, who operated on a commission basis, sold the vast majority of DuPont Company powder. The two most significant were Francis Gurney Smith (1784-1873), who operated out of Philadelphia, and Furman L. Kneeland (1824-1884) of New York, who commenced his association as an agent in 1849 and became General Agent for Sales in New York in 1861. Many of these agents were hardware store owners and dry goods merchants who had contracts with the DuPont Company to sell in rural and mining districts. Others were prosperous merchants in large industrial centers who sold powder on their own account. The letters frequently contain reports of local business conditions, the prospects for sales of powder, and customer complaints. Collectively, the letters mark the growth of the DuPont Company sales network from the regional to the national scale.