My argument cannot be against selection, simplification, emphasis, which are inevitable for both cartographers and historians. But the mapmaker's distortion is a technical necessity for a common purpose shared by all people who need maps. The historian's distortion is more than technical, it is ideological; it is released into a world of contending interests, where any chosen emphasis supports (whether the historian means to or not) some kind of interest, whether economic or political or racial or national or sexual.
    -- Howard Zinn, People's History of the United States, p.8