A young man (William Bloom), at the deathbed of his father (Edward Bloom), tries to reconcile his memories of his dad with who he really is. Whereas he always saw his father as an irresponsible liar, he comes to understand his dad's exaggerations and their roots in reality.
The book is written in a chronological (although they may not appear so at first) series of tall tales. Despite the novel's first-person narration, there is no present tense part of the book. The various stories are Will's retelling of tales that Ed has told about his life. The 'My Father's Death Take' chapters are William planning out his final conversation with his father in his head and how it will go, so that when the actual conversation takes place, he will be able to get to bottom of the truth and find a way of truly understanding his father.
The book draws elements from the epic poem The Odyssey, James Joyce's Ulysses, and American tall tales. The story of Edward Bloom also includes at least seven of the Twelve Labors of Hercules.
The subtitle "A Novel of Mythic Proportions" may be a reference to the dimensions of the Penguin edition, which make a Golden ratio. Conversely, the dimensions of the Penguin edition may derive from the subtitle. The Golden ratio dimensions carry through the bodies of type on each page, and are most apparent on the opening pages of each chapter.