A common published form of biblical exegesis is known as a Bible commentary and typically takes the form of a set of books, each of which is devoted to the of one or two books of the Bible. Long books or those that contain much material either for theological or historical-critical speculation, such as Genesis or Psalms, may be split over two or three volumes. Some, such as the Four Gospels, may be multiple- or single-volume, while short books such as the deuterocanonical portions of Daniel, Esther, and Jeremiah (i.e. Book of Susanna, Prayer of Azariah, Bel and the Dragon, Additions to Esther, Baruch and the Epistle of Jeremiah), or the pastoral or Johannine epistles are often condensed into one volume.