Howard Zinn book A People's History of the United States tells history from minorities perspective, the loosing sides and the ones affected by certain courses of actions while traditional texts usualy stand on the other side, telling history from the country's traditional point of view.
This shows historians sometimes tell history from one point of view not considering that in every situation there're always at least two different perspectives. Objectivity is rarely found when History es told as historians usualy tend to incline to one side or another.