Todenhöfer is not a Spiegel journalist. Not at all. DER SPIEGEL gets its book data from der Buchreport which uses sales info from a few hundred actual bookstor

Todenhöfer is not a Spiegel journalist. Not at all. DER SPIEGEL gets its book data from der Buchreport which uses sales info from a few hundred actual bookstores. Thus the list is not 'garbage', but a represents what bookstores sell and what is currently trending. The list is also filtered by some criteria, which are listed on the SPIEGEL site.