Abd al-Salām ben āli , known as Abū l-alt al-Hirawī  and Khwāja Aba alt, was a close companion of Imam al-Rida (a) and a scholar of hadiths and kalam(theology).

After Imam al-Rida's (a) arrival in Khorasan, he went there and accompanied him. He transmitted the Golden Chain Hadith as well as the story of Imam al-Rida (a) beingmartyred by al-Ma'mun al-'Abbasi. Abu l-Salt passed away in 236/851 in the period of Tahir b. 'Abd Allah b. Tahir's rule in Khorasan. His burial place is located on the Mashhad-Fariman road 10 kilometers from Mashhad. Pilgrims of Imam al-Rida's (a) shrine visit his mausoleum as well.

Abu l-Salt wrote a book about Imam Rida's (a) death. The book is mentioned by al-Najashi. It is cited by al-Shaykh al-Saduq in his 'Uyun akhbar al-Rida.

The fact that reports of Imam al-Rida's (a) death are often transmitted by Abu l-Salt shows that his book was available at least until the 5th/11th or even 6th/12th centuries.