My full review: https://youtu.be/v6MNUKqa5dE 
 Not my favorite book in the series, but still fantastic. If you have trouble remembering who's narrating in this book, I suggest listening along to the audio book which has different readers based on who is narrating. I loved being able to see Four's perspective. 
 I wanted to see what was beyond the wall ever since I found out there was one. What lays beyond didn't disappoint. I love how the whole series explores genes vs. personality, what happens when you try to force people into labels and groups, the ethics of scientific experimentation and manipulation, what it means to face your fears and what is real bravery. Characters with realistic emotions, reactions and struggles. This final book was emotionally draining, but at the same time did justice to the characters and world they live in. Not the ending we wanted, but the one this series deserved.