Barry Greenstein is an American professional poker player and former mathematics postgraduate student. He has won a number of major events, including three at the World Series of Poker and two on the World Poker Tour. Greenstein donates his profit from tournament winnings to charities, primarily Children Incorporated, earning him the nickname "the Robin Hood of poker". He was elected into the Poker Hall of Fame in 2011.

The Poker Hall of Fame is the hall of fame of professional poker in the United States. Founded in Las Vegas, it was created in 1979 by Benny Binion, the owner of the Horseshoe Casino, to preserve the names and legacies of the world's greatest poker players and to serve as a tourist attraction to his casino. Binion was known for the creative ways in which he marketed his casino. In 1949, he convinced Johnny Moss and Nick "The Greek" Dandolos to play high-stakes poker heads up where the public could watch them. In 1970, he invited a group of poker players to compete in what would be the first World Series of Poker (WSOP). When Harrah's Entertainment, later known as Caesars Entertainment, acquired the rights to the WSOP in 2004, it also assumed ownership of the Poker Hall of Fame. Currently, membership in the Poker Hall of Fame is handled directly by the WSOP.