Cusp is a science fiction novel written by Robert A. Metzger, in the category of hard science fiction. It deals with two perpendicular rings running along the Earth's surface, that act as cosmic jets, using ionized hydrogen. In this universe, the fusion of organic and non organic material is an everyday thing. Multiple characters are portrayed in the story, and it is told from 3rd person.
Carl Hays reviewing for Booklist said that "Metzger’s background as a telecommunications scientist enables a brilliant, sprawling vision of humanity in the late twenty-first century."[1] Kirkus Reviews was mixed in their coverage saying that Cusp was "Overcomplicated by several orders of magnitude, with anonymous characters mystifyingly associated with a ferocious and largely unfathomable plot. Still, minds will boggle at the extravagance of Metzger's imagination.[2]