Although the German version of The Three Investigators starts with The Secret of Terror Castle, it continues through The Mystery of the Cranky Collector, then picks up with the "Crimebusters" series and continues on with German-language originals from there (starting at number '56'). The German-language originals started in 1993 with books by Brigitte-Johanna Henkel-Waidhofer. She wrote 16 books for Kosmos. After her era ended, several other authors continued to write in the series at the rate of six books per year (in contrast to the U.S. series, which published one new story every year or so after Robert Arthur's death). In Germany, the franchise has also been the source of audioplays, films and graphic novels. Source: Wikipedia (en)