Yisrael Meir ha-Kohen Kagan (January 26, 1838 – September 15, 1933), known popularly as the Chofetz Chaim, after his book on lashon hara, who was also well known for the Mishna Berurah, his book on ritual law, was an influential Lithuanian Jewish rabbi, Halakhist, posek, and ethicist whose works continue to be widely influential in Orthodox Jewish life. Source: Wikipedia (en)