Before I Fall is the story of high-school student Sam, who is killed in a car accident whilst being driven home from a late-night house party (not a spoiler, it happens right at the beginning). But rather than moving on, she finds herself reliving the day of her death over and over again in a Groundhog-day type scenario. As she starts the same day afresh every morning, Sam must learn that every action and even inaction that she takes has consequences for those around her.I liked the main character of Sam in this book. At the beginning, she was not a very nice person - not the sort to start bullying others but the kind that will readily join in without feeling guilty. She's distant from her parents and has cut her best childhood friend out of her life in order to be seen as popular. She's obsessed with wearing the right thing, saying the right thing and even eating the right thing at lunch-time. She's self-absored in the way that only teenagers can be, and Oliver wrote this part beautifully. But then as the book went on, I got to see Sam slowly change and mature. Of course the whole process was sped up by the groundhog day scenario, but it read like a real reflection on the growing up process that happens to all of us. I appreciated that Oliver didn't create a perfect main character (like I've seen in a lot of YA books) but instead let us watch her develop throughout the course of the story.When I was reading Before I Fall, I felt as though I had gone back to my own teenage years, as Oliver perfectly captures what it is like to be a teenager when you aren't sure of yourself and the world of school and your relationships with other teenagers are the most important things in the world. At points I wanted to reach into the book and shake the characters, saying "it does get better when you get to the real world." And that's the essential problem for me with this book and with YA books in general - I don't always want to be transported back to my teenage years. In fact, I'm quite happy to be out of them.But Before I Fall is definitely one of the best YA books I've read for a long time. It's addictive, hard to put down, well written and contains a cast of decently developed secondary characters. There are no stereotypical teens present in Oliver's book. As the story goes on, you do find yourself rooting for Sam and hoping that she will be able to change herself into a better person. I would recommend this book to anyone who likes YA, or anyone who wants to be reminded of what it is like to be a teeanger.