The quartet is divided into three sections: Thymos_Phrenes_Chthonios.
Thymos means "blood vapour" and is one of the elements that souls of the dead in the underworld completely lack, therefore they crave it and seek it out; they also lack "breath consciousness" or phrenes.
The term "chthonic" [thon-ik] generally means "underworld." However, Hillman thoroughly elaborates that its true meaning extends "below the earth and beyond it" (p.36) into invisible, non-physical and far distant psychic realms as opposed to being limited to a "primitive earthiness" that limits us to the physical and fertile "underground." Hillman weaves a captivating and expanded perspective on "chthonic" and the deeper mysteries of the invisible, drawing from such sources as Greek and Egyptian mythology, Freud, Nietzsche, and more. "The underworld is a realm of only psyche, a purely psychical world_underworld is the mythological style of describing a psychological cosmos. Put more bluntly: underworld is psyche." (p.46) -the publisher