Note: This credit is only for the German books written after the original English series was discontinued.
Die drei Fragezeichen (Die drei ???) is the German name for The Three Investigators. The Three Investigators books have always been very popular in Germany. Some of the character names were changed for the German editions: Jupiter Jones was renamed as "Justus Jonas", a German adaption of his original name, while Pete Crenshaw is named "Peter Shaw". Bob Andrews retained his original name, and the chauffeur's name is Morton. In 1964 Random House and the German publisher Kosmos started to publish the translated 43 original books. In 1993 Kosmos began publishing new written books by German authors. As of 2018, over 150 new titles have been released.
There is also an off-shoot series targeted at a younger audience titled Die drei ??? Kids.