Billie Jean King is an American former World No. 1 professional tennis player. King won 39 Grand Slam titles: 12 in singles, 16 in women's doubles, and 11 in mixed doubles. She often represented the United States in the Federation Cup and the Wightman Cup. She was a member of the victorious United States team in seven Federation Cups and nine Wightman Cups. For three years, she was the United States' captain in the Federation Cup.