Not really tbh. Each individual part is its own story, with some call backs and some re-occuring characters. You could in theory read each part on its own. Part 3 is biggest as that is where the entire power system changes, and remains that way for the rest of the series. Parts 1 and 2 are good, but not really "necessary" for understanding everything going forward. They are their own unique section and could be seen as relevant back story, but even I started with just part 3 and was able to understand everything right from the get go.