Their problem is deeply rooted in the conventional ways in which textbooks
have presented history as a succession of facts marching straight to a
single, settled outcome or resolution, whose significance one can neatly evaluate.
But once students have learned the fundamental importance of keeping
their facts straight, they need to realize that historians may disagree widely
on how those facts are to be interpreted. (National Center for History in the
Schools, 1996, p. 26)