** spoiler alert ** 
 This review contains spoilers. Big ones. 
 This was a really quite a disturbing read - like a trainwreck you can't stop looking at. Horrifying. 
 The slow reveal via the letters will alienate some readers but I found it a useful device. I guessed that Franklin was dead, but it wasn't until the final few chapters did it dawn on me that Kevin might have killed him too. Perhaps like when Eva turned up at the school not even thinking Kevin would be the perpetrator, I didn't want to believe it would all end up so tragically. 
 This is not a book I wish to keep a copy of - it's a disturbing, difficult read for many reasons - though I am glad to have finally marked it as 'read'. Despite feeling horrified I was also oddly fascinated by all the relationships and the different dynamics between the main characters, (even when at times I hated all of them). Shriver does an excellent job of letting the story unfold and exploring the age old question of nature vs nuture.