Born in Montana at the end of the 19th century, the American designer Edward McKnight Kauffer—known as E. McKnight Kauffer—was a modernist at heart. He traveled the world and in 1915 settled in London. There, his cutting-edge posters, book covers, and illustrations quickly made him the country’s most celebrated graphic designer. “A New McKnight Kauffer Poster Will Appear Here Shortly,” was the message papered onto vacant billboards, in anticipation of his next work. Kauffer believed that art shouldn’t just reside within museums but should weave through daily life. Cooper Hewitt presents 150 design objects by Kauffer, including some of his most radical illustrations. —E.C.