The protagonist, Mattia Pascal, finds that his promising youth has, through misfortune or misdeed, dissolved into a dreary dead-end job and a miserable marriage. His inheritance and the woman he loved are stolen from him by the same man, his eventual wife and mother-in-law badger him constantly, and his twin daughters, neglected by their mother, can provide him with joy only until an untimely death takes them. Death robs him even of his beloved mother.
To escape, he decides one day to sneak off to Monte Carlo, where he encounters an amazing string of luck, acquiring a small fortune. While reading a newspaper on his return home, he discovers, to his immense shock and delight, that his wife and mother-in-law declared an unknown corpse to be his own. Faced with this sudden opportunity to start afresh, he first wanders about Europe, and finally settles down in Rome with an assumed identity. His character develops in unexpected, even admirable, ways. Yet one admirable act brings the protagonist a crisis, followed by additional crises that lead him to conclude that continuing with his plans will entail only misery for those he loves, precisely because his entire life, including the precious liberty he thought he had gained from his past, is now a lie. He ultimately decides to fake his own death and return to his original life. But even that proves difficult; his family and town have long since adjusted to his "death," and his own adjustment of character prompts him to have mercy on his now remarried wife. So the twice-dead Late Mattia Pascal reduces himself to a figure outside the mainstream of society, a walk-on part in his own life.
Despite the bizarre and macabre plot, the book is written in a warmly humorous style. Mattia is, essentially, a comic character, and the novel at times becomes almost satirical. Pirandello's concern with the nature of identity, which figures strongly in such plays as Six Characters in Search of an Author and Enrico IV, is also at the philosophical core of this novel.