It is Paul who writes, based on the translation of the Epistles of Saint Paul & of the Acts of the Apostles by Ronald Knox

Father Ronald Cox's The Gospel Story contained the whole story of the Life of Christ told in the words of the Evangelists, printed on the left hand pages; his Commentary on the right-hand pages, directly opposite the Scripture text. Students immediately saw the advantage of this arrangement: one book to work from, open in one place, no searching for references, etc. This book is a sequel to The Gospel Story. It takes up at the point in Scripture where that left off, at the Descent of the Holy Ghost. The arrangement of the books is the same: on the lefthand pages of It Is Paul Who Writes, the text of the Acts of the Apostles and the Pauline Letters runs continuously; directly opposite is the Commentary. Again the Scripture translation of Msgr. Ronald Knox is used, with a few alterations which he approved. A chronology of St. Paul's life, a table of the Epistles for Sundays and Feast-days, and three maps of St. Paul's journeys are provided. ** http://archive.org/details/itispaulwhowrite00knox