Mishnah Berurah (Clarified Teaching) is a work of halakhah by Rabbi Yisrael Meir Kagan also colloquially known by the name of another of his books, Chafetz Chaim (Desirer of Life). His Mishnah Berurah is a commentary on Orach Chaim, the first section of the Shulchan Arukh, which deals with laws of prayer, synagogue, Shabbat and holidays, summarizing the opinions of the post-Medieval rabbinic authorities. It is widely used as a reference and has mostly supplanted the Chayei Adam and the Arukh HaShulchan as the primary authority on Jewish daily living among Ashkenazi Jews. He displays a tendency towards stringency though he does include lenient opinions.