The author of this book (Solomon?) seems to enjoy life and encourages others to do so. He's also very reflective about his life and work.
He also totally ripped off the Byrds!
One of the most interesting things I've read so far comes at 3:19-3:22. The author clearly states that the beasts of the earth and man will share the same fate. That both will return to dust and that he/we can't know that there is an after life.
His philosophy? Enjoy life while you're here. Sounds like an Atheist to me!
Between Proverbs and Ecclesiastes, the Bible seems to be turning into a more positive book. Quite the change from the killing and mayhem of the first half of the Old Testament.
Why the change? I think it's because God has had no direct input for the last several books. Humans seem to be very pleasant when he's not around! ;-)