Abstract
After the Holy Qurᾱn, Ḥadith and Sῑrah is the ultimate source of guidance for all human beings. Infact just like other fields, Sῑrat Nigᾱr has a very close relation to the life of Prophet S.A.W. Sῑrah is the field in which many scholars shown their interest. Muḥammad bin Isḥᾱq is one of them, who was born in 80 Hijri at Madῑna. He is known as predecessor in Sῑrah writing. His book "Sῑrah ibn Isḥᾱq" is considered as the original source in this field, But there are some observations regarding his authenticity which propagate a diverse sort of thinking about him. In the article under reference we have tried to bring these observations under discussion and identifie their position in light of scholastic arguments.