This quartet of novels is very good value in this one edition and I certainly recommend the purchase. The general premise is that in the distant future humanity has split between those who live upon gigantic moving cities and those who live in more conventional towns. The moving cities tend to prey upon each other for resources. The story arc follows the adventures of some key players in the subsequent war between the two ideologies/lifestyles. These key players include an apprentice historian, a fairly murderous orphan girl, an unscrupulous author, and some deadly cyborgs.
The strength of these novels is the author's ability to make the reader engage with the principal characters. I found myself really caring about what happened to them. This was just as well because the plot in places (especially the first fifty or so pages) requires an extraordinary amount of effort to maintain suspension of disbelief. What - a problem maintaining suspension of disbelief in a postapocalyptic steam punk novel! Surely not. No, it wasn't the premise or themes I struggled with. It's just that the author heavily relied upon luck and coincident to get his characters through certain episodes, which to me felt like cheating. And a little bit of thought usually suggested such coincidences unlikely.
The novels are all very 'clean' and well suited to teenagers and young adults. Their atmosphere reminds me of old adventuring 1950s and 1960s movies (the same type that the Indiana Jones movies emulated). Certainly they are fast paced and quite enjoyable. The characters evolve over the four novels in a manner I found quite satisfying.
All in all, very good. Well done Mr Reeve.