A recently reprinted memoir by Frederick Douglass has footnotes explaining what words like 'arraigned,' 'curried' and 'exculpate' meant, and explaining who Job was. In other words, this man who was born a slave and never went to school educated himself to the point where his words now have to be explained to today's expensively under-educated generation.
Ever Wonder Why? and Other Controversial Essays (ed. Hoover Inst Press, 2006)