At the end of Leviathan, the Clankers and the Darwinists did actually manage to work together in order to save all their lives. But... you know that couldn't possibly last. And things immediately get tense in Behemoth, a steampunky adventure story filled with political intrigue and Middle-Eastern grandeur -- and Scott Westerfeld expands his story far beyond the main characters. 
 It doesn't take long for Alek to realize that he and his companions are about to be imprisoned by the British, once they're no longer useful. Fortunately, they're headed to the Ottoman Empire. But when the Leviathan lands in Istanbul (NOT Constantinople, Dr. Barlow reminds us!), it becomes obvious that all is not well. England's autocratic "borrowing" has angered the sultan, who is more inclined to favor the Germans... who also happen to be in the area. 
 In the meantime, Deryn is being sent off on a secret mission that may give the British a triumph over the Ottoman navy, even as Count Volger blackmails her with her little gender secret. And Alek has escaped to somewhere in Istanbul, where he falls in with a small band of rebels -- which could lead to a shocking shift in power. 
 The first book was all about escaping from the Germans/Austrians, but "Behemoth" focuses on a the political upheaval of war. Scott Westerfeld spends a LOT of time on diplomatic and political matters in this book, and the delicate balance of nations. But don't worry, politics doesn't make this book boring. 
 Instead, Westerfeld makes this story into a steampunk thriller, with smoothly-intertwined subplots and some tense action scenes (being chased through the Istanbul streets on a giant mechanical beetle!). His prose is strong, smooth and detailed, and Westerfeld painstakingly explores some new technology, both Darwinist ("living" diving armor!) and clanker (mecha elephants!). 
 Downside? I was a little disappointed by the revelation of what was in Barlow's eggs. I just... expected something a bit more epic. 
 And the characters are given a lot more development as well. Alek has grown into a young man who is more cautious, sensible and more open-minded; and Deryn is sent on dangerous secret missions while trying to keep her gender a secret. Westerfeld drops some hints that romantic feelings are blooming between these two, although Deryn ends up in an awkward love triangle of Shakespearean proportions. 
 Scott Westerfeld spins up a solid, suspenseful adventure story in "Behemoth," and lays the groundwork for a brilliant climax. Absolutely brilliant.