I found this while looking for some German mystery fiction. It wasn't very good. Perhaps it lost something in translation but reading it was hard going: the writing was stodgy and the characters unusual but unappealing. Originally published in 1992, it's the second story featuring Gerhard Self, a 69 year old private investigator. Self is hired by a government official to find his missing daughter. The trail leads Self to a psychiatric hospital and a couple of odd doctors. 
 The title gives away at the least the first third of the story i.e. the missing girl, Leonora, is not what she appears and neither is the concerned but unseen father. Self finds himself investigating a terrorist act that no one appears to have noticed, another murder (that nobody cares about, least of all the reader) and other things that I can't remember since they weren't at all memorable. 
 Okay, so the book wasn't as bad as all that. Self's armchair philosophising is sometimes amusing. One paragraph had me laughing out loud and involved a complaint about German trains running late. Self also has an unlikely ally in the form of detective who likes to build miniatures with matches. But ultimately, these quirks alone do not a good mystery novel make.