The manager at Parlin, a bistro in Dusseldorf, started talking about an author I should read, but I’d never heard of him: Erich von Däniken.
Wikipedia is not the most reliable source but this paragraph about Mr. von Däniken could be material for a short story or a novel:

‘Following his release, he became manager of the Hotel Rosenhügel in Davos, Switzerland, during which time he wrote Chariots of the Gods?, working on the manuscript late at night after the hotel's guests had retired.[7] The draft of Chariots of the Gods? (German Erinnerungen an die Zukunft) had been rejected by a variety of publishers. Econ Verlag (now part of Ullstein Verlag) was willing to publish the book after a complete reworking by a professional author, Wilhelm Roggersdorf. (Roggersdorf was a pseudonym used by de:Utz Utermann, a former Schriftleiter of Völkischer Beobachter and Nazi bestseller author.[8]) Against all expectations, the book gained widespread interest and became a bestseller. In 1970, the Spiegel stated a hype about Däniken and called it Dänikitis, a pun on Meningitis and other infections.[9] Däniken gained 7 percent of the books turnover, 3 percent went to Utermann.[10] In December 1964, Däniken wrote Hatten unsere Vorfahren Besuch aus dem Weltraum? ("Did our Ancestors have a Visit from Space?") for the German-Canadian periodical Der Nordwesten.[11] Chariots of the Gods? was accepted by a publisher in early 1967, and printed in March 1968.[7] In November 1968 Däniken was arrested for fraud, after falsifying hotel records and credit references in order to take out loans[7] for $130,000 over a period of twelve years. He used the money for foreign travel to research his book.’

Did our ancestors receive visitors from outer space is too important a question to leave it to Mr. Von Däniken.
I, for one, am convinced that visitors from outer space are among us.

Unfortunately, the manager at Parlin couldn’t say much about Von Däniken, only that Von Däniken’s books had changed his life, but he refused to go into details.