Thomas Boss worked for great British gunmaker Joseph Manton, before becoming a pieceworker to the London trade. In 1891, John Robertson was taken in as a partner and under his control the firm was established as one of London's best gunmakers, rivaled only by James Purdey. Current Boss shotgun prices (2019) begin at about 88,000 British pounds for O/U and 68,000 for SxS. Double rifles are very limited in production and prices begin at about 100,000 pounds. Used values are shown in U.S. dollars. Boss values will vary greatly depending on vintage, configuration and engraving. These values should be considered to be generalizations.