The History of teaching  History is important to know. In the span of time from 1960 until today teaching history has become a kind of brainwashing meant to subvert the values of democracy and undermine the Constitution of the USA and the free market system. Allen Bloom in his very important book the Closing of the American Mind went into a detailed description of how the social studies and humanities departments of universities have become brain washing factories. Though it is easier to learn History than Math and more fun also still that does not give either of these departments much value. So be careful.  It is best to learn books of history that were written before 1960.