Usul al-Ifta wa Adabuhu is a guide to the principles and etiquette of issuing fatwas in Islamic law, authored by Taqi Usmani, a Pakistani scholar and former judge of the Federal Shariat Court and the Supreme Court of Pakistan. The book is considered one of the primary textbooks for advanced Fiqh students and is widely used in Islamic seminaries. It covers various aspects of fatwa, including its definition, types, and conditions for issuance, as well as providing guidelines for those seeking fatwas and the role of the mufti in the process. Drawing on a variety of sources, including the Quran and the teachings of Islamic scholars and the Prophet's companions, the book provides a thorough overview of the subject matter, including the history and development of Islamic jurisprudence and the importance of adopting a particular school of thought.

Muhammad Taqi Usmani SI, OI, is a Pakistani jurist and a leading scholar in the fields of Qur'an, Hadith, Islamic law, Islamic economics, and comparative religion. He was a member of the Council of Islamic Ideology from 1977 to 1981, a judge of the Federal Shariat Court from 1981 to 1982, and a judge in the Shariat Appellate Bench of the Supreme Court of Pakistan from 1982 to 2002. In 2020, he was selected as the most influential Muslim personality in the world. He has been conferred the title of Shaykh al-Islām for his knowledge in Islamic studies. He is considered a leading intellectual of the contemporary Deobandi movement, and his opinions and fatwas are widely accepted by Deobandi scholars and institutions worldwide, including the Darul Uloom Deoband in India. Since 2021, he has been serving as the Chairman of Wifaq ul Madaris Al-Arabia. His father, Shafi Usmani, was the Grand Mufti of Darul Uloom Deoband and migrated to Pakistan with his family after the partition of India in 1948.