I always love Jennifer L. Armentrouts books so it's no surprise I loved this one too. Her books are always fun and the relationships and characters are always perfect. I always fall in love with her characters, her books are just so easy to read and I fly by them. I needed to read this book I have read almost all Jennifer's young adult books (save Cursed because I heard it was really bad) so I already knew I was going to give this one a go, especially after all the great reviews on it. 
 Don't Look Back has more of a serious plot going on than what she usually writes. I think she's trying to change it up instead of the regular paranormal books she switched to a mystery, triller. Her characters are also a lot different the Carson (crush/boyfriend/thing) isn't a bad boy and a douche and Sam (the main character) isn't bitchy like her normal characters are. Listen closely though I'm not saying I hate all the characters in her other books I like them a lot actually, their bitchynes and douche assery is amusing. 
 One thing I missed during this book was the characters sense of humour that is usually present in her books. This book didn't have any of that and her usual kick-ass heroine. 
 One thing that was an improvement was her originality. This book wasn't original their are so many books on this sort of thing, but it is a major improvement from Half Blood. You'll know what I'm talking about if you read it too. Through and through it is a copy of The Vampire Academy. I still enjoyed Half Blood because I loved the main protagonist Alex... But no you can't just copy a book like that. Ever since that now for every single one of Jennifer's books I compare it to other things (which is never good while reading a book) this one reminded me of Mara Dyer and Pretty Little Liars. Urg! And I hate myself for making these comparisons because it was a great book. 
 To be completely honest the killer in this book is really predictable I guessed it half way through the book, and then my sister spoiled it for me (damn you). For me their was no shock factor and there wouldn't have been even if I wasn't spoiled. 
 Now I need to stop focusing on the bad because otherwise your going to wonder why I gave it 4 stars. There is something compelling about this book that drew me in. It wasn't the mystery of the "what's going to happen next" it was the characters, I loved them. I don't know if that's a good enough reason to give the book 4 stars but I really enjoyed the book because of them, I think I'd be more of a 3.5 but I'm nice so I round up. But Jennifer's characters, it isn't just Carson and Sam that I liked, there was Scott and... Scott (Sam's brother) ok so maybe I only really liked three characters but I liked them a lot so it's all good. Then there was Carson and Sam, I wasn't sure how I was going to like this not bad boy and non Bitchy heroine but I liked them they weren't as entertaining and funny but I still really liked them it was a nice change. 
 If you still don't know what this book is about Sam has been missing for a week Along with her best friend Cassie. Sam was found but not Cassie, Sam has no recollection of her memories and thus what happened that night. So Sam gets to start over but she learns the person she used to be was a total bitch and she and Cassie were more like frenemies than friends. Sam tries to make things better while slowly gaining memories on what happened that night.