The German artist Sigmar Polke, celebrated as an “early and astute adopter of American Pop art,” died last Thursday in Cologne, Germany. He was 69. A refugee from East Germany, Mr. Polke grew up in Dusseldorf, where he began his career as an artist in the early 1960s. Sharply critical of communism and capitalism alike, Polke used a range of media, from painting to photography to watercolor, to parody both systems of politics and economics. For more on the art and life of Sigmar Polke, see Sigmar Polke: History of Everything, Paintings and Drawings, 1998-2003, edited by John R. Lane and Charles Wylie. Obituaries for Mr. Polke ran in the NYTimes and The Guardian, among other print and electronic publications