1835-1910 19thcentury 20thcentury 500 american americanliterature americatwain authenticity(philosophy)inliterature counterfeitsandcounterfeitinginliterature criticismandinterpretationtwain doublesinliterature historyandcriticism humorousstories identity(psychology)inliterature inliterature knowledge mark nationalcharacteristics passing(identity)inliterature philosophyinliterature psychoanalysisandliterature psychologicalfiction sciencenews scientificliterature selfinliterature splitselfinliterature