This book discusses the theory that the Psalter was compiled with the specific intention that it should be used as a book for private spiritual reading. It is argued that if this were so, the work of the final editors would not have been confined to arranging the psalms in a particular order but would have included additions and interpolations intended to give the whole book a new orientation. An investigation of selected psalms shows that although the Psalter may have become a book for private devotion not long after its compilation, there is little evidence that it was compiled for that purpose.