This was an amazing addition to the Divergent series, and is a must read for any fan, regardless of how you felt after reading Allegiant. You can purchase these individually as well as purchasing the whole book, but I highly recommend just getting the bound copy where all the stories are in one place. Plus, there are 3 extra scenes that provide a great ending to the book. There aren't really connected, but it's something extra that you get rather than purchasing each one individually. Also, by purchasing the book you can read them in the order they are meant to be read, and it is more of a complete story. While each story can be read separately, I think you can become much more connected to Four by reading them all back to back. Each novella leads into the next one, and we see a side of Four that we have never seen before, even in the last book where we were treated to his POV. 
 Throughout the course of the book, we slowly watch the progression of Tobias into Four, and we find out some surprising information that will definitely give some readers a shock. We get to see scenes that were only mentioned in passing, such as the fight between Eric and Four, Four getting his tattoo, and Four discovering the term Divergent. We get to see the struggle Four faces with being in Dauntless, especially because of the events of his past. 
 There are also some scenes between him and Tris that are simply adorable and leave you wanting to re-read the series all over again. The ending of The Traitor: A Divergent Story is the shock that I mentioned, and while I had a feeling I knew where it was going, it was surprising nonetheless when the title finally made sense. 
 I highly recommend checking this book out as it provides a nice sense of closure for the series. I loved learning more about Four, and Veronica has made me love him even more after reading this book. And to send you off, one more Theo James gif for ya ;) 
 Happy reading :)