Steffi Graf has won 22 Grand Slams~!
There are at least 3 who have won singles calendar Grand Slams: Steffi Graf, Margaret Court and Mo Connolly. Court has also won doubles Grand Slams.
Pre-Open Era: Margreet Court Open Era: Steffi Graf
Steffi Graf Martina Navratilova (she was the first to win all of them) Serena Williams
steffi graf won that in 1988 ...all four major slams plus olympic gold...
There have been seven players that have won the Grand Slam four times. The one player that won it four times in the same years was Steffi Graf.
In the "open era" only 3 players have done this in a calendar year, considering Singles play Steffi Graf, Rod Laver and Margaret Court (Stefan Edberg did it as a junior)
Steffi Graf, I believe
Steffi Graf of Germany
Steffi Graf's real name is Stefanie Maria Graf.