I guess that an example of a book in which the underdog was stood up for would be The Shadow Children Series by Margaret Haddix. In this series people are not alolowed to have three children. however these thrid children are still born and go into seclusion. Their struggles to survive and regain their freedoms are what the whole thing is about. Several teenage heroes arise out of this strife and take charge of the situation. The way that the author shows how they suffer from this discrimination and how badly they want to live a normal life was at the time, very moving. While this is an extreme situation, even a more normal setting this kind of bullying exists and people get hurt because of it. It happens to me every once and a while from people who are ignorant and judge of appearance. All you need to do to stop this is to simply prove them wrong. However, sometimes people are too scared. In this case, What is need is someone to step and in help that person. More often than not, this never happens. But when that rope is thrown, it makes a world of difference to that one victim.