During this time, he was exposed to the writings of the French author
Émile Zola, who used the philosophy of
Positivism and the literary current of
Naturalism to challenge the conditions of French coal mines. Lillo observed similar conditions in Chilean mines and set out to improve the condition of the workers by dramatizing their plight. Lillo wrote many short stories (collected in
Sub Sole and
Sub Terra that sparked the interest of social activists. ==See also==