Ecclesiastes is written from the perspective of an individual who referred to himself as teacher. This individual, apparently, had at one time enjoyed wealth, wisdom, pleasures and acheivements. He'd also seen, and been moved for, oppressed people and those who were alone. All this, he comes to realize is all meaningless. We must serve the Lord God while we live and be content and grateful for what we have. All of us die one day, no matter how much we've acheived, how much money we have, how much wisdom we've acquired; we all reach the same end.