Ulum al Qur'an
The Makkan Group
According to many scholars, this group of mufassirun from among the tabi’un are the most knowledgeable in tafsir, because they learnt about it from 'Abdullah b. 'Abbas. They are many in number, and among the best known out of many others are Mujahid (d.104/722), 'Ata' (d.114/732) and 'Ikrima (d.107H).
Mujahid, the best known among them, is reported to have gone through the Qur'an thrice with Ibn 'Abbas and to have asked him about the 'when' and 'how' of each verse that had been revealed. [Taimiya p. ;102.]
A complete book of tafsir by Mujahid has been published. It is based on a manuscript from the 6th Hijra century and is edited by Surti. [Surti, A.: Tafsir Mujdhid, 2 vols., Beirut, n.d.]
Example:
Humaid b. Qais Makki reported: I was with Mujahid and we were circumambulating the house (Ka'ba). A man came and asked whether the fasts of penalty of an oath should be observed continuously or severally. Humaid replied that if he liked he could observe them severally too! But Mujahid said: Not severally, for the reading of 'Ubayy b. Ka'b is thalathi ayyamin mutatabi'at, i.e. to fast three days continuously'. [Muwatta Malik, No. 617.]