Bear with me. I complain a lot at first but also go over the positives. I found that this book had a lot of potential. While Cunningham is certainly not the first to write about a world above the clouds, he did do it in a refreshing way. I found their world fascinating, but there were so many flaws with it. I understand that building a new world, especially such a fantastical one such as one above the clouds, is challenging, but Cunningham made some very big mistakes. The biggest peeve for me as I read this was this: they live on mountain tops. Cunningham very explicitly describes Heliopolis. It is made up of an agricultural sector, an artisan one, the bureaucrats, and then royalty and lords. HE COMPLETELY FORGOT THE MINES. Most of their city is built of stone. Their ships are built of metal and wood. The Cloudfarers wear shiny metal armours. They have many metal weapons. Marcus literally says that they brought the "iron age" to the world below. Cunningham in no way accounted as to how this metal was acquired. You certainly cannot mine a mountain top. At least, not one you are living with. There is no place they could have gotten enough metal and stone to build the citadel. The architectural side might have made sense if Heliopolis had been built done into the mountain rather than on top of it. The only possible explanation is that there are uninhabited mountains that are mined and that they get their metal and stone through trade but this seems like a very expensive and untrustworthy method of acquiring materials.
Second problem I had was how they never discovered the world below. This was never addressed. Sure, there are huge predatory birds that probably killed those that have attempted to hike down, but that still does not explain how aerocruisers never made it down. Also even if the Heliopolitans never made it down, how come some other citadel never discovered it? I find it difficult to believe that there would be dangerous predators on every single mountain. It also seems like a useless secret to keep if another citadel discovered it. I also feel like he tried to make the cloud dwellers seem very intelligent but ???? Many of the technological advances we made were because we discovered the Earth was round and could account for gravity and such. At some point, we do find out that they do know that their world is round - they mention the equator. I just feel like it was supposed to be this /big/ reveal that there was something beneath the clouds but it just seems so improbably that they never made it lower than the clouds with their technology. Obviously, the ornithopter dude saw it and then flew back up. Also, I understand that their world is apparently made up of a lot more water than ours because the clouds are always very dense. The world under is always gray, however, which means that the plants there must have found some other source of nutrition other than photosynthesis. I just feel like there's so much that was unaccounted for.
The ending felt kind of like I was being flipped off. The climb was very boring. I know nothing of mountain terminology so I didn't even know what was happening half the time. The worst was the mapmaker just dying out of nowhere. That was so extra. I really wished it had a more conclusive ending, or at least switched perspective so that we could also know what was happening in Heliopolis, perhaps from Marcus' tutor's POV. The characters were also all very 2D. Cunningham focused so much on their actions and their world that he completely forgot that he was supposed to be writing realistic and relatable characters. Also I find it very odd that the underdwellers were not more advanced. They have access to more resources and the struggle to survive seems greater there.
POSITIVES: Honestly, I thought the story was a very interesting read. Would have read it all in one seating if I could've afforded too. While the world was flawed, I did think it was very interesting. I especially enjoyed the underworld and how they have different races of people. I liked that he accounted for gravity and the air being different below and above the clouds. I really liked the Nullmaurs. I found them fascinating. While they could use a lot more development, I like that Cunningham considered the lack of vision in the underworld and gave them reflective eyes like a cat's. Other than the fact that it feels like the story was cut short, I really liked the plot.
Overall, there was a lot of potential. While I really enjoyed this book, it feels like it's just the rough draft.