It was appreciated by a close friend of Svevo's, James Joyce, who presented the book to two French critics, Valery Larbaud and Benjamin Crémieux.

The previous novels follow a naturalistic model; Zeno's Conscience, instead, is narrated in the first person, and is focused entirely on the character's thoughts and feelings.

Moreover, Zeno is an unreliable narrator, since in the very first page his doctor, publishing the diary, says that it is made of truths and lies.

Even in the third-person narrative of Una vita and Senilità, the reader knows only the point of view of the main characters; and these are, or feel, unfit to live.

The novel is presented as a diary written by Zeno, published by his doctor (who claims that it is full of lies).

The diary, however, does not follow chronological order; instead, it is structured in large chapters, each developing a particular theme (tobacco addiction, his father's death, the story of his marriage, and so on).

Only the last chapter is a real diary, with pages referring to specific dates at the time of the First World War.

He is restless and shifts positions for comfort often, even though the doctor says that staying in bed would be good for his circulation.

His last action will haunt Zeno until he reaches his sixties, as he is not able to tell if it was a final punishment or just his illness taking over his body.

When he is starting to learn about the business world, he meets his future father-in-law Giovanni Malfenti, an intelligent and successful businessman, whom Zeno admires.

Zeno's affection for both Augusta and Carla increases and he has a daughter named Antonia around the time Giovanni passes away.

Carla misrepresents Ada as Zeno's wife, and moved by her beauty and sadness, breaks off the affair.

They hire two workers named Luciano and Carmen (who becomes Guido's mistress) and they attempt to make as much profit as possible.

Guido's gambling on the Bourse becomes very destructive and he finally tries to fake another suicide to gain Ada's compassion.

Renting a house in the village of Lucinico, he sets out on a casual morning stroll without his hat and jacket – when the outbreak of the war between Italy and Austro-Hungary turns the area into a war zone and Zeno is separated from his wife and children by the frontline.

The final entry is from March 1916, after Zeno, alone in wartorn Trieste, has become wealthy by speculating and hoarding, though money has not made him happy or pleased with life.

Human advancement has given mankind not more able bodies, but weapons that can be sold, bought, stolen to prolong life.