There are a lot of different threads and all of them are managed well and given enough space to be explored properly. There's the, somewhat stereotypical, lonely ex-cop private investigator with the career back story, ex-wife and kid he adores but hardly sees. There's a complicated tangle of Peri, her employees and their child. And woven in all of that is the research corporations, new religions, surgeons, corrupt officials, social welfare groups, police, armed forces and alternative societies that make up this city. One of the things I thought was particularly well achieved was the description of the science of creating fliers. I think writers need to go one of two ways when it comes to the science part of the fiction, either explain it fully and comprehensively or leave it totally alone. The reader is given the information through Zeke's visit to the doctor in charge of his son's impending surgery, and it is explained in detail. For me, it totally worked and seemed completely realistic and not at all impossible. But the very best part of the book is the description of flight. I really can't stress enough how real it feels, I could see everything Peri sees, feel everything she feels, I was so up with Peri soaring through the air. And I learned a lot. I had no idea air is so complicated! It is really worth picking up a copy for this reading experience alone.