Fairytale imagery
The Book of Three is a novel which uses motifs and imagery from fairytale stories in a fantastical way. That sets the story properly in the mythic imagination of the reader, so that if a person wanted to derive arguments from the artwork, it could be done through archetypal analysis. That isn't really necessary though, because the fairytale imagery involves a debriefing section at the end of the book where the novel's sage explains to the protagonist (and the reader) what the moral of the story really is.
Epic imagery and royalty
The characters are not regular old people. They are heroes and royalty, legendary figures that can be thought of as manifestations of certain properties. The evil enchantress is a symbol for what could be described as the insidious evils of conspiracy and seduction. Her magic powers are not fixed upon ethical standards, and so she gradually becomes something more archetypally poignant. The novel considers heroism a kind of "nobles oblige," calling on inherently important people to fulfill their fateful destinies.
Animal imagery and self-discovery
The process of becoming one's self is described by animals in this story. The titular Three can be thought of as a reference to the three animals, all of which are mythic. The first is the sacred oracle pig who has escaped, a la Jason and the Argonauts. The second mythic creature is a "What is it" or a Gurgi, a mythical animal best known for its perplexing features. The perplexity is like a curiosity that pulls the hero through a lengthy series of trials. The third animal is the bird of death which is unleashed in fully epic proportion to wreak havoc on the earth. The book explains that these images are representations of a transformation process that the hero's journey causes.
Death and transformation
Death is shown through basic, obvious imagery and then becomes confused substantially when the sagacious woman of wisdom explains to protagonist and reader alike that what appeared to them to be a death was actually a transformation into something else. That discover is the real "holy grail" of the novel, so to speak, and that is the future which is foretold by the omens of the novel's inception. The hope for death as a kind of transformation would be a hope for redemption of suffering, as if suffering were only inherently tragic if life ends in death.
