Emanuel Lasker was a German chess player, mathematician, and philosopher, best known for being the World Chess Champion from 1894 to 1921. His long reign made him one of the most influential figures in chess history, and he contributed significantly to chess theory and strategy. In addition to his chess career, Lasker earned a doctorate in mathematics and published works on various subjects, including philosophy and psychology. He was known for his deep understanding of the game and his ability to adapt to different playing styles, which helped him maintain his championship title for nearly three decades.