Abū Bakr Aḥmad ibn al-Ḥusayn ibn ʿAlī al-Bayhaqī (384–458 AH / 994–1066 CE) was one of the foremost ḥadīth scholars, jurists, and theologians of the fifth/eleventh century. Born in the district of Bayhaq in Khurāsān, he studied under many of the leading scholars of his age, most notably the renowned traditionist al-Ḥākim al-Naysābūrī. He traveled extensively in pursuit of knowledge, collecting and transmitting ḥadīth from a vast network of teachers across the Islamic world. A distinguished adherent of the Shāfiʿī school and Ashʿarī theological tradition, al-Bayhaqī devoted much of his scholarship to demonstrating their foundations in the Qurʾān, the Sunnah, and the reports of the early Muslim community. Among his most celebrated works is al-Sunan al-Kubrā, one of the largest and most influential compilations of legal ḥadīth in the Islamic tradition. Through his numerous writings on ḥadīth, jurisprudence, theology, and ethics, al-Bayhaqī exerted a profound influence on later Sunni scholarship, and his works remain widely studied to the present day.