What is "nabou"

Nabou is a 1968 science fiction novel by German author Günther Krupkat. Written as a sequel to his 1963 novel Als die Götter starben, Nabou narrates an expedition into the interior of the Earth. A member of a research team investigating Earth's crust is revealed to be a cyborg, or "Biomat," left by an advanced spacefaring people called the Mejuans. The encounter between the humans and the alien representative is a comparative class encounter between advanced socialist aliens and human societies in a "lower stage" of development without open class conflict. A 1989 survey ranks it as the 13th most popular East German science fiction novel.