Comparative Tafsir, apart from Tafsir methods and schools, compares Shia and Sunni’s views. In this domain, there are Tafsir foundations and the Quran concepts. Considering Tafsir foundations, the Shia and Sunni’s principles and assumptions about understanding the Quran are considered in two sections as the common and specific foundations. One of the factors affecting the controversies among the Tafsirists is their attitude towards the existence of common and specific foundations. In this book (the first book of the comparative Tafsir research series), the foundations are reviewed and reexamined in order to detect the strengths and weaknesses of Shia and Sunni’s Tafsir foundations and to provide a ground for testing the distinguishing Tafsir points. The other books study the concepts of the Quran in a comparative manner.