Rabbeinu Yitzchak b"R Yosef on Bereishis רבינו יצחק ב"ר יוסף - בראשית

It has been perhaps 500 years since we have merited a new commentary on the Torah written during the life of the Rashba. 

Rabbeinu Yitzchak the son of Rabbeinu Yitzchak was a close associate of the Rashba. He cites many unique peirushim which he heard from the Rashba. He also cites many additional commentaries from other great commentators, including: Rabbeinu Chananel, Rav Shmuel ben Chafni Gaon, and Rabbeinu Yitzchak Aderes, [The commentary of Rabbeinu Chananel on the Torah, published in various forms over the generations, was created using this manuscript. However, as one can see in the introduction, based on this manuscript we are able to improve the previous editions of the Peirush Rabbeinu Chananel.] As one can see in the footnotes, he is clearly a source for Rabbeinu Bachya, Rabbeinu Yehoshua ibn Shauib (whose commentary on the Torah has numerous editions with great textual variations and should merit a new edition), and the Peirush referred to as Sodos HaRamban meyuchas to Rabbi Meir ibn Sula (the introduction and addendum to the work goes to great length explaining the relationship between the two works).