In this book he lists 542 references to joy from the Holy Scriptures. If the Bible is a book of joy dear ones, we ought to be a joyous people.
Happiness has to do with happenings.
But the joy the Bible speaks of has to do with your relationship with the Lord Jesus Christ. It's a joy you can't put into words. It's a joy that bubbles up from a well that is deeper than our understanding on intellect. Our Lord was about to be betrayed and crucified. This is the joy of Christ.