The two most important writers of the last half of the nineteenth century were

The two most important writers of the last half of the nineteenth century were Henry James & Samuel Langhorn Clemens

Explanation:

Henry James was considered by many a key transitional figure between literary realism. He is known for the big quantity of social material he made.  The Portrait of a Lady, The Ambassadors, and The Wings of the Dove. are some examples of that.

Samuel Langhorn Clemens was better known by his pen name Mark Twain. He was a humorist, entrepreneur, publisher, and lecturer. Two of his most famous novels were The Adventures of Tom Sawyer and the Adventures of Huckleberry Finn.

chapter i -- paris: september, 1792

a surging, seething, murmuring crowd of beings that are human only in name, for to the eye and ear they seem naught but savage creatures, animated by vile passions and by the lust of vengeance and of hate.

during the greater part of the day the guillotine had been kept busy at its ghastly work: all that france had boasted of in the past centuries, of ancient names, and blue blood, had paid toll to her desire for liberty and for fraternity.

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