During the Second World War, in 1941-1943, he created the Ladies of the White House series, commissioned by World Book Encyclopedia. Portraits ranged from Martha Washington to Eleanor Roosevelt, whom he met after completing the project. His animals are some of his major works. New York’s American Museum of Natural History currently has fourteen huge panels on display showcasing his dinosaurs, penguins, and majestic rainforest creatures. In the 1970s, still in the United States, he published a series of books in collaboration with Dorcas MacClintock (who wrote the copy), including “A Natural History of Giraffes” (1973) and “A Natural History of Zebras” (1976). The “Poet of Shadows” – as he became known in the United States – died at the age of eighty-eight in New Rochelle (New York).