I remember reading this and getting so attached to the story, I would read it every free moment I had: on the bus, while crossing the street (not a good idea), while on the toilet.

The story is in perfect Dürrenmatt style: simple but weird, it made me feel like I was working on the story, instead of reading an already planned one. I also really enjoyed how it develops: things happen as they happen, not as they should in a good novel, which made it all more interesting, because while you could foresee how a normal writer would have developed the plot, you can never foresee how Dürrenmatt does it.
The writing and the style are simple and precise, so I would say you can read this book in german even if your german is not perfect.

I would recommend this story to anyone who is looking for a different kind of mystery, because this book will not only fascinate you with its weird plot, but it will also make you think how the creepy world you are reading about is actually just our world.