I wanted to read this because I was hoping it was similar to Jules Verne. Verne often imagined futuristic machines that were used in contemporary times (like 20,000 Leagues Under the Sea). The difference between this book and Verne's stories is that Westerfeld takes futuristic ideas (even for now) and puts them in the past. This blending of past and future is referred to as steampunk.
The book started slow, but had lots of action and interesting ideas. The second book is already out, so there is no waiting to find out what happens next.
Click here to find more info about this book from the Westfield Washington Public Library.