The premise irony
The premise is built on an invocation of dramatic irony. The promise of the premise is that the reader will learn about some scandal that Iris committed in her life, because she is confessing her untold deeds on her death bed. The irony of her death bed confession is dramatic in nature because she basically tells the reader to expect something crazy, but without explaining what that crazy scandal might be. This forms a kind of intrigue—"drama." The drama of the book is the guilt of human experience.
Metanarrative and irony
This book is a seemingly-semi-autobiographical book about an author who writes seemingly semi-autobiographical books which include books within books about authors. The point is that meta-narrative is used to obfuscate any hope of determining which elements of the plot are derived from Margaret Atwood's personal life. In a way, the meta-narrative acts as a dynamic force field between the reader and the author, because the information is filtered through fictitious layers. That means that the book can be taken as pure fiction or as autobiography, but meanwhile, the plot seems to prove the antithesis, showing that all art is an expression of self and one's experience of time.
The betrayal irony
When Iris discovers that her sister had been raped for years under threat of blackmail, the drama of that revelation is clear. But nothing could have prepared Iris for the identity of the offender; it is her own grumpy, exacting husband who plays the part of a tyrant while secretly using his power to betray the whole family. This irony is most poignant because of his intimate relationship to the protagonist. Suddenly, Iris's entire perception of reality changes and she realizes that she is married to a monster.
The sudden challenge of survival
When Iris discovers her husband's capacity for evil, she does what she feels is safest for her child; they withdraw from him and live as if her could not support them. That ironic choice to intentionally go the more difficult way makes the character aware of the dramatic irony which privilege had prevented her from understanding. Now that she has to make ends meet for her and her daughter alone, she realizes the genuine challenge of that task. Survival, something she rarely had to discuss or consider, now becomes the challenge of her life.
The affair
From the onset of the novel, it is clear that this confession, this death-bed confession, will be something scandalous, and as the dramatic tension raises through time, the likelihood of Iris's scandal becomes more obvious. Eventually she reveals her big secret; the fodder for her writing career is the emotional thrills of her scandalous affair with Alex. That affair is ironic in both dramatic ways (because it is a plot twist) and in situational ways (because that complicates the novel's thematic defense of fiction and autobiography; meta-narrative complicates this duality further).
