Athar as-Sunan is a book of hadith, or sayings and actions of the Prophet Muhammad, compiled by the 14th century Islamic scholar, Muhammad bin Ali al-Shawkani. The book focuses on the traditions and practices of the Prophet Muhammad, as well as the actions and sayings of his companions. It is considered a valuable resource for Muslims seeking to learn more about Islamic traditions and practices. The book has been translated into multiple languages and is widely read and studied by scholars and laypeople alike. It is an important part of Islamic literature and has had a significant impact on Islamic scholarship throughout history.