In 1936, Maurice began his collection of late 19th- and early 20th-century Impressionist paintings and sculpture (after his death, the collection was given to Harvard University and is housed at Harvard's Fogg Museum in Cambridge). Most of his acquisitions were made during World War II. As the 1940s began Steinbach was the firm's investment banker, Klingenstein the stock picker and trader, Hottinger the administrator, Hilson the deal man, Bernhard the contact with other Wall Street firms, and Maurice was increasingly involved in public affairs and personal interests. Banking clients included Continental Baking and Helena Rubenstein; the firm's foreign offices were closed because of World War II. Cuban operations provided shelter from the excess-profits tax during the war years. In 1941, Maurice was named president of the American Jewish Committee; the following year, he moved to Washington DC as a member of the War Production Board. In 1946, Maurice led the American chess team as its non-playing captain against the Soviet team in Moscow, in a match played over the radio. Laband retired, making a personal gift of one week's salary to every employee of the firm. Bob Bach joined the firm, after graduating from Princeton and serving in the U.S. Navy. The following year, Maurice donated in Suffolk County to the U.S. Fish and Wildlife Service as a wildlife refuge (the Wertheim National Wildlife Refuge). He and his wife Cecile had previously managed the area as a private waterfowl conservation and hunting reserve. In 1948, Maurice published a book entitled "Salmon on the Dry Fly". In 1949, W&Co. had nine partners: Maurice, Klingenstein, Hilson, Steinbach, Jones, Goldstone, Bach, Hottinger and Allen DuBois (who headed the underwriting department). Wilbur Cowett joined the company, working closely with Hilson. Maurice died in 1950, at age 64. His obituary noted that he was a trustee of the American Wildlife Foundation, a noted fisherman, a tournament chess player, founder and director of the New York Theatre Guild, an equestrian, and director of the Underwood Corporation, the Cuban Atlantic Sugar Company, the Hat Corporation of America, and the Bond Stores Company. He was also a trustee of Mount Sinai Hospital and the Federation of Jewish Philanthropies. Entering the 1950s, W&Co. was one of the leading U.S. firms in trading foreign securities. Investment-banking clients included Armour and Company, Food Fair, Spiegel, Shoe Corporation and Miles Shoe.