There is only ONE book of Psalms and it has 150 chapters.
It is true that there is only one book of psalms however within
psalms there are five books that correspond to the first five books
of the Bible:
Book 1: Psalms 1-41
Book 2: Psalms 42-72
Book 3: Psalms 73-89
Book 4: Psalm 90-106
Book 5: Psalms 107-150