The first thing that I noticed on the cover of the book is the massive fingerprint. This alone suggests crime and mystery. This expands to the handing phone. It looks like an old phone with the wire and further suggesting the book is based in an historical time. "Geiger" the name of the book, translating this from german to english, it means 'violinist'. Or it can mean 'Fiddler' Someone who plays a Violin. Something like Sherlock Holmes playing the violin at this window waiting for a crime. The word can also mean a person who cheats or swindles, especially one indulging in petty theft. Inferring that the antagonist is a 'Fiddler', a thief?