Super mild spoilers.

This book should be required reading before seeing Rogue One. The story brings so much depth to the characters we will see in the film, especially Galen Erso and Orson Krennic. The novel also went a lot deeper into kyber crystals than we've seen in the new canon (which was nice timing after the Ahsoka novel - I feel like we've gotten a lot on kybers recently). The book left me wanting more about Jyn's character, but perhaps that's the best way for it to end since it is a prequel to Rogue One!