This book for those people who believes in God, but their faith is in doubt due to obstacles, difficulties, injustice in life and they are thinking that really God exists or not!!!! It conveys the message that whatever happens, it happens for good even it is bad for you at that moment. Don't fight with God and whatever happens, just accept it and try to improve it with your hard work without worry of result. Other authors write boring self improvement books like lectures and here, Paulo Coelho saying those things in the form of stories.
Definitely not for me, but I took as a nice story and enjoyed it. You too will enjoy.