The last verse of Psalm cvi. indicates the close of the fourth book. It contains but seventeen psalms, and is the shortest book of the five. The fifth book includes the remaining forty-four psalms, among them the "Songs of David," or Pilgrim Songs, sung by the people on their journeys to Jerusalem to keep the solemn feasts. It is probable that this fifth book was compiled by the authorities in charge of the temple worship, and that they at the same time collected the other four books and put them all together, completing in this way the greater book of sacred lyrics which has been so precious to many generations not only of Jews, but also of Christians. Various unsuccessful attempts have been made to classify these books according to their subject-matter. It is plain that the first two are composed chiefly of the oldest psalms and of those adapted to the general purposes of worship; the third book reflects the grief of the nation in the Captivity; the fourth, the joy of the returning exiles; the fifth contains a more miscellaneous collection. The Jewish scholars recognize and sometimes attempt to explain this arrangement of the Psalms into five books. The Hebrew Midrash on Psalm i. I., says: "Moses gave the five books of the law to the Israelites, and as a counterpart of them, David gave the Psalms consisting of five books." This is, of course, erroneous; the present collection of Psalms was made long after the time of David; but it is not unlikely that some notion of a symmetrical arrangement of the Psalms, to correspond to the five-fold division of the Law, influenced the compilers of this Praise Book. Of the contents of this book, of the peculiar structure of Hebrew poetry, and of the historic references in many of the psalms, much might be said, but this investigation would lead us somewhat aside from our present purpose. It may, however, be well to add a word or two respecting some of the inscriptions and notations borne by the Psalms in our translation. Many of them are composed of Hebrew words, transliterated into English,--spelled out with English letters. King James' translators did not know what they meant, so they reproduced them in this way. There has been much discussion as to the meaning of several of them, and the scholars are by no means agreed; the interpretations which follow are mainly those given by Professor Murray:-- First is the famous "Selah," which we used to hear pronounced with great solemnity when the Psalms were read. It is a musical term, meaning, perhaps, something like our "Da Capo" or, possibly, "Forte"--a mark of expression like those Italian words which you find over the staff on your sheet music. "Michtam" and "Maschil" are also musical notes, indicating the time of the melody,--metronome-marks, so to speak; and "Gittith" and "Shiggaion" are marks that indicate the kind of melody to which the psalm is to be sung.