This is the second in this series about an alternative steampunk world set against a backdrop of WW1 and I enjoyed it as much as the first. I like the main characters - Alek and Deryn/Dylan. They're realistic and make mistakes and yet are still likeable. I do want to shake Alek though and point out to him that Dylan is really a girl. 
 I love the idea of this world and the different Darwinian creatures from the Leviathan which is a living airship to Bovril who attaches himself to Alek and then Deryn. I suspect that is intentional foreshadowing that those two will end up together. I'm hoping so. Also enjoying the way in which the author is modeling events and historical locations on our world, yet with subtle changes. 
 Meantime I'm waiting impatiently for the third book in the series and conclusion to this story.