Mockingjay is the third and last (sad face) book in the Hunger Games trilogy. The rebellion against the Capitol has begun, and Katniss is needed as the Mockingjay, the face of the rebellion. But this may involve giving up herself and all that she is, and, when it comes down to it, is it really worth it?
I read two-thirds of Mockingjay in one day, which should give you some idea of how compelling it is. Every chapter brings a new revelation, sometimes two or three, and certainly the emotional whirlwind is quite intense, especially towards the beginning, when it hasn't had a chance to sink in yet. But there were fewer emotional high points than there were in Catching Fire - moments like the mockingjay dress and that bit where the victors all hold hands on live television. Mockingjay is altogether a much grimmer book. Death! Destruction! Betrayal! etc. Although at one point I did catch myself going "Oh no" out loud.
I still love the moral complexity of the world that Collins has created, the way that even the rebels can do terrible things and, at times, there doesn't seem to be much to choose between the two sides. It is, at least, a moderately "realistic" portrayal of how a real rebellion works.
But it didn't catch my imagination as Catching Fire (hah, a pun) did. The storytelling seemed a bit jerky, with odd leaps around the country and between scenes, and some unresolved tensions. Still, a worthy ending to Katniss' saga.