Who is Captain Samuel Vimes from Guards! Guards! and what is their importance?

Captain Vimes is the leader of the Night Watch. He has done several things in his career that landed him this position as a punishment and has taken to drinking. Although he is a drunk and believes there is no reason to fight crime or arrest criminals, he becomes angry when the dragon begins to take over the city. He fights to make things right for the city and the people that live there. Vimes moves from being a drunk to receiving accolades for his part in saving the city. He acts as if he doesn't care about his job, but when he is fired later he fights to get his job back and continues to work toward ridding the city of the dragon. He has a poor self image but has many redeeming qualities that eventually prove to be the salvation of the city and himself. He even allows himself to consider a relationship at the end of the story.