Who is Aleksandr Ivaonich Luzhin from The Defense and what is their importance?

Luzhin is the main character of the novel, a man who does not fit into his society and is lost and isolated in himself. Until the very end of the novel, Aleksandr is referred to exclusively by his surname of Luzhin. This causes some confusing language in the early parts of the novel during which the father still lives, as father and son are both identified by the surname. This parallel proves more than textual. Luzhin's obsession with chess corresponds to his father's sexual proclivities. It isn't until just after his death that Aleksandr is referred to by his full name, posthumously separated from his father.