Chess legend and innovator who created the ELO rating system, which calculates the relative skill levels of players in competitor-versus-competitor games.
He was a professor of physics at Marquette University.
His rating system was used internationally for most of the 1970s and 80s and he wrote the book The Rating of Chessplayers, Past and Present in 1978.
He and his family moved to the United States from Hungary when he was very young.
He was a contemporary of fellow great chess thinker Savielly Tartakower.