Super sleuth, 1 
Ecke, Wolfgang.
Humphries, Stella.
Humphries, Vernon.
London Magnet Books
1979
With answers
These translations originally published: as 'Be a super sleuth with the case of the face at the window', London : Methuen, 1978. - These stories originally published: in German, in volumes entitled: 'Der Schloss der roten Affen', 'Der Mann in schwarz' and 'Das Gesicht an der Scheibe'. Ravensburg : Otto Maier Verlag, 1971-1972
Children's literature, German.