I read this book while I was in high school and loved it. Having just re-read it, I see that there are flaws in the story, but overall I think the book is still entertaining. The characters ARE somewhat one dimensional, but there are so many of them it would have been hard to fully develop every single one and still move the story along. I think one thing that is lacking is that Ms. Duncan might have taken more time illustrating WHY these girls feel so strongly about Irene. Is is just because she's young and different? Does she reach out to them in any way? A few reviewers have commented that the ending was not all that shocking. Just to put this in perspective, when I was in high school, school shootings were unheard of--there were no metal detectors, no security, nothing (at least not where I went to school). And when I first read it I was indeed shocked at the turn of events, and also horrified, as I recall. I also wondered why no one seemed to catch on to Irene sooner, but overall it's still a good read.