The book that would deserve to be banned first in the world would be a catalog of banned books.Gilbert K. Chesterton (1874-1936), Orthodoxy (1908; rpt. London: The Bodley Head, 1957), p. 44:
Das Buch, das in der Welt am Ersten verboten zu werden verdiente, wäre ein Katalogus von verbotenen Büchern.
There is a thought that stops thought. That is the only thought that ought to be stopped.