Every window on Alcatraz has a view of San Francisco.

These words, from the opening chapter “Toward a Topography of the Parallel Universe,” illustrate the “parallel universe” inhabited by the mentally ill. Kaysen describes the ease with which a person can slip into this other reality, tempted by glimpses through the thin “membrane” that separates the sane from the insane. Once inside, a new set of rules replaces the conventions of life on the outside. The cruel irony of life in the “parallel universe” is embodied by a person’s perfect awareness of the reality left behind. The afflicted mind is still very much aware of the world it has abandoned. Kaysen compares this alternate reality to a prison, but notes that even the worst prisons occasionally allow glimpses of something beautiful. Thus, being mentally ill can be worse than being in prison.