Habib Muhammad bin Salim bin Hafiz was a Ba Alawi scholar born in the village of Mishtah near Tarim in 1332 AH, corresponding to 1914. He was raised by his father, Habib Salim bin Hafiz, who first taught him the foundational Islamic sciences and then took him to Tarim for further study.
His teachers included Habib Abdullah bin Umar al-Shatiri, Habib Alawi bin Abdullah bin Shihab and his maternal grandfather Habib Ali bin Abd al-Rahman al-Mashhur. He also studied with Habib Jafar bin Ahmad al-Aydarus, Habib Muhammad bin Hadi al-Saqqaf and Habib Mustafa bin Ahmad al-Mihdar. In the Hijaz he learned from scholars including Shaykh Muhammad al-Arabi al-Tabbani, Sayyid Alawi bin Abbas al-Maliki, Sayyid Muhammad Amin Kutbi and Shaykh Hasan al-Mashat. He also travelled to India and Pakistan and met hadith scholars there, including Shaykh Muhammad Yusuf al-Kandahlawi.
Habib Muhammad wrote introductory works in jurisprudence and grammar, compiled al-Tadhkirah al-Hadramiyyah on knowledge required for women, recorded teachings of Habib Alawi bin Shihab and authored a biography of Habib Abdullah al-Shatiri titled Nafh al-Tib al-Atiri.
During the socialist period in South Yemen he was required to report regularly to the security authorities. On 29 Dhu al-Hijjah 1392 AH, corresponding to 1973, he left to report to them and was never seen again. Ba Alawi accounts remember him as a victim of the regime, but the surviving account does not document a confirmed place or date of death.
Sources
Muwasala, source biography: https://muwasala.org/2015/10/10/habib-muhammad-bin-salim-bin-hafiz/