I received an E-ARC of this book from the publisher for possible review.I was lucky enough to get a finished copy at a charity event, which I am giving away -- enter on my blog, YA Romantics! US only, ends 3/4/13.To me, this series defines high-concept: what if love were viewed as a disease? After finishing Requiem, it seems to me that this entire series is an exploration of different types of love. In Delirium, Lena faces the prospect of her impending cure, then falls in love with Alex and risks everything to be with him. In Pandemonium, Lena faces life after a loss, and learns more about herself as a person as she faces life in the wilds, helps infiltrate the DFA (Deliria-Free America) and grows close to Julian. If Delirium is about first love and Pandemonium looks at love after loss, then I'd say that Requiem explores the idea of love as sacrifice.Lauren Oliver's writing is beautiful and lyrical in all three books and I've enjoyed this entire trilogy. But after finishing the series, I'd say Delirium was my favorite. I preferred the single point of view, loved all the incredibly creative excerpts from The Book of SHH and other sources, and just found it more gripping to read about life within this dystopic society than life on the outside in the Wilds.Like Pandemonium, Requiem has shifting points of view. While Pandemomium shifted chronologically from chapter to chapter, alternating between "now" and "then" in Lena's point of view Requiem shifts between Hana's point of view and Lena's. I will probably be in the minority on this, but I much preferred Hana's chapters in Requiem, probably because they reminded me of Delirium. Hana has been cured, and she's not quite herself, but I still found her situation complelling. Like Lena in Delirium, Hana is counting down the days to an important date -- her wedding to the mayor's son -- and as that date grows closer, her anxiety about the ceremony and her groom begin to grow. She starts sneaking around Portland, investigating a hunch. She's also keeping a BIG secret from Lena.Lena's chapters in Requiem follow her work with the resistance in the Wilds. There are a lot of characters (most from Pandemonium, a few new) that I couldn't always keep straight, and a lot of hiding and skirmishes and moving from point A to point B. It was frustrating to me that Lena uses her group's precarious situation as an excuse to refuse to talk about or deal with the dramatic event at the end of Pandemonium. While I suppose this was realistic -- the group is trying to plan a rebellion while evading Regulators -- it was also frustrating.In Requiem, Lena and Hana are each haunted by the past and tormented by guilt. There's a story -- borrowed from the Old Testament and the adapted in The Book of SHH -- that preoccupies both women. Thinking about that story -- in either version -- made me a little nervous about the ending of Requiem. Basically, the SHH version of the story ends in tragedy and the Biblical one in self-sacrifice. I won't tell you which way things go in Requiem, but I'll be very curious to see how other readers react.