Scholarly efforts to understand the Hopi concept of hikwsi were rather unilateral and led to the oversimplified conclusion that hikwsi is a Hopi linguistic equivalent for the soul. This article attempts to shed some light on this important philosophical concept in a Hopi language perspective, particularly as applied in an explanation of human structure and behavior. In the Hopi belief, death does not end a person’s presence in the physical world, but marks a transition from one state of being to another or, in other words, from one form of experience to another. On the fourth day after death, a person’s breath (hikwsi) leaves the body and goes to a place which represents the other realm of existence, not separated from the world of the living, but different in that this realm is unmanifested, unseen, and not accessible to the senses. In ethnographic and anthropological literature this symbolic place has been described as the Underworld, Lower World, Third World, or the World of the Dead (muski; mus-ki, “corpse-home”). According to Emory Sekaquaptewa,this concept can be expressed by a Hopi word, atkya, which literally means “down below.”’ The word atkya can refer not only to an area at the bottom of the Grand Canyon (Ongtupqa) called Sipuapuni, from which the Hopi came out of the Underworld, but also to an area seen from the tops of Hopi mesas in the southwestern direction. This area is marked with kiikiqii (literally, “ruins”;metaphorically, “footprints”),places inhabited once by Hopi ancestors (Hisatsinom) before they arrived at Hopi present settlements, such as, for instance, Homol’ovi,Wupatki, Tsor’ovi (Tuzigoot), and others. Hikwsi of the dead is believed to have the ability to return to the Hopi mesas in visible forms of clouds, rain (or katsinam) and act as an animating force in the sensuous world of the living.