“All of a sudden, he created an amazingly large number of works in a completely new style,” said Felix Klee of his father, the artist Paul Klee, in a 1988 interview. “More than 1,200 in the single year of 1939.” A new exhibition focuses on Klee’s work from that year, when failing health (he died in June, 1940) and a world heading toward war led to his most inspired paintings. Klee’s earlier work was influenced by Expressionism, Cubism, and Surrealism. His late work transcends all categories. —J.V.