Pioneering and influential American-born artist (1834–1903), best known for his distinctively evocative portraits, city- and landscapes, and the “Arrangement in Gray and Black,” aka “Whistler’s Mother.” ALS, signed with his sketched “butterfly” signature one 6 x 4 page affixed to a slightly larger card, no date. In full: “Here are the letters my Dear Salomon. You have plenty of time for this next Sunday. Just a line or two as we said last night—and then put in the correspondence itself in its entirety. Do ask Phil Robinson from me to have it. Always….” Accompanied by a vintage typescript from the Lincoln Library in Shippensburg, Pennsylvania. In very good condition, with mounting as note, heavy vertical fold, light wrinkling and a few tiny tears, and mild toning and soiling. The writing is dark throughout. R&R COA.