The Boy Who Changed the World is a wonderful tale of 5 different men in history who, by doing one small or simple thing (or by making one small or simple choice/decision), were able to change the world in a big way.
The book was short enough that my 3 yr old daughter sat on my lap and allowed me to read it to her and it kept her attention. I doubt that she understood it, but she enjoyed listening to the book while the attractive illustrations kept her focused.
The Boy Who Changed the World is a wonderful book for children in the second/third grade and up. I believe my third grader would actually understand that HE could make a difference by one small kindness to a stranger or a friend. It would be a wonderful gift or book to use in Children's ministry. It also makes a great companion for a family that is reading The Butterfly Effect.