The earlier stories are mostly independent (the last few in the series build on previous stories). I would recommend starting with the first book, The Silver Pi

The earlier stories are mostly independent (the last few in the series build on previous stories). I would recommend starting with the first book, The Silver Pigs because there is a romance that starts and continues. The central character is what today we would call a "private eye". https://en.wikipedia.org/wiki/The_Silver_Pigs https://en.wikipedia.org/wiki/The_Silver_Pigs