When I read Leviathan, I thought that the first half was like a giant prologue, just introduction to the world, the premise, and the characters. Then the second half of the book was spent getting the two main characters to be in the same place at the same time and heading in the same direction. Things just started picking up at the end, and then, well, it was over. I finished Leviathan vaguely dissatisfied with the story but really, really eager to read the second book. Because the world, characters, and premise Westerfeld spent an entire book setting up were really freaking awesome, even if he did need to take up an entire volume just to get the readers situated in the world and the characters situated in the plot.My impression was correct. This book had all the action and plottiness that was missing from the first one, and it had it in spades. I feel like I know the characters much better now than I did at the end of the first book, and I'm excited to see how they change and develop in the third book, Goliath. This is one of the rare instances where a second book in a series not only equals the first in quality but far exceeds it. Definitely a must-read.