Grand Ayatollah Sheikh Muhammad-Hasan al-Najafi (Arabic: محمد حسن النجفي, romanized: Muḥammad Ḥasan al-Najafī; 1785–1850),[1] also known as Sahib al-Jawahir (Arabic: صاحب الجواهر), was a prominent Shiite religious authority and author.

He was most known for his books of Jawahir al-Kalam Fi Sharh Shara'i' al-Islam, a 42-volume work on fiqh.

[2] Though the exact date of Muhammad Hasan's birth is unclear, Agha Bozorg Tehrani, a renowned Shi'ite scholar from Iran, puts it at around 1212 lunar Hijri (AD 1797).

His family lineage includes numerous religious scholars and his brother, Muhammad Hossein, who was killed as a young man.

In fact, after the establishment of the Usuli school in Shia thought, scholars such as Muhammad Baqir Behbahani, Moḥammad Mahdī Baḥr al-ʿUlūm, and Shaykh Ja'far Kashef al-Ghita developed Usulism from those foundations.