John Albert Kramer (August 1, 1921 – September 12, 2009) was an American tennis player of the 1940s and 1950s, and a pioneer promoter who helped drive the sport towards professionalism at the elite level. Kramer also ushered in the serve-and-volley era in tennis, a playing style with which he won three Grand Slam tournaments (the U.S. Championships in 1946 and 1947, Wimbledon in 1947). He also led the U.S. Davis Cup tennis team to victory in the 1946 and 1947 Davis Cup finals. Wikipedia
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