Since September 2010, some of the world’s most famous detectives have been cracking cases in an imaginative audio-play series from Germany’s Romantruhe Audio label that’s aimed at adults and young people alike. Sherlock Holmes & Co stars the eponymous sleuth in many episodes, but other investigators also get to shine, including Professor Van Dusen, C Auguste Dupin and Father Brown. Some stories are adaptations of original cases and others are new mysteries altogether. Here we select the most ingenious and entertaining episodes—so you can solve the riddles, too.