Grenzen der Vergangenheit?

From Author Wars - https://authorwars.com/books/grenzen-der-vergangenheit-1678475.html

Overview:

Title: Grenzen der Vergangenheit?
Author: Kurt Mahr
Year: 1975
Type: Essays
Series: Perry Rhodan Computer
Number in Series: 29

Variant Titles:

1975. Grenzen der Vergangenheit?