Grand Ayatollah Sayyed Mohammad Sadeq Hussaini Rohani is an Iranian Twelver Shia Marja currently residing in Qom, Iran. He was born in the city of Qom during Muharram 1345 AH.
 Sayyed Sadiq Rohani started his teaching career in the city of Qom with his father teaching Arabic Grammar. Then, in the year 1355 AH at the age of 10, he travelled to study under the renowned scholars of the Islamic Seminary of Najaf. Due to his exceptional intelligence he was able to complete the elementary studies (called Sat’h) in only one year. After being examined by Khoei, he started his higher Islamic studies (called Dars’e Kharej) of “Fiqh” and “Usool” at the age of 11. He received his Ijtihad Authority at the age of 14, from Grand Ayatollah Abul-Qassim Khoei. He became a Marja, after death of Grand Ayatollah Borujerdi, at the age of 35.
Fiqh al-Sadiq in Arabic is one of his books in 41 volumes and more than 20,000 pages.