The Gambler is the tale of a man named Alexei with a passion for -- no, an addiction to -- roulette.
In Dostoevsky's own words, .
all his vital sap, all his energies, his impetuosity and boldness will be absorbed by roulette.
He is a gambler, but not just an ordinary gambler .
My hero is, in his way, a poet, but he feels ashamed.
and he feels its ugliness [the ugliness of his addiction] deeply.