I don't often feel the need to review the prequels after I have reviewed the series separately, but, after reading The Kill Order (a prequel to James Dashner's Maze Runner series), I felt the need to weigh in.
Arguably, this is the best written book of the entire franchise. But that may have more to do with the fact that I would classify this as more of an adult book than YA.
The premise of the book is to give you an idea of what happened from the time of the Sun Flares until the time the Flare virus was spread among the people. The synopsis I read led me to believe it would enlighten me on how WICKED was formed, but it didn't really touch on that.
Instead, it is the story of Mark and Trina and their life in the Post-Sun Flare settlements when, one day, a Berg (think large flying machine) swoops in and starts firing darts at the residents of the settlement. Mark and Alec (one of the group leaders) hop on board the Berg to find out what is going on and after what they find shocks them, they work their way back to the settlement to try to put their little group back together again.
What they find when they arrive is horrifying. The darts contained a highly contagious virus designed to wipe out the settlements to better insure the survival of those in the cities. This fast acting virus has decimated the population on their settlement. Mark and Alec lead the charge to right this wrong and make those responsible pay for it.
I don't want to give much more away because it truly is a captivating read. Very adventurous, lots of action. Makes you question government decision making at every turn. I highly recommend it. But definitely read it AFTER you've read the trilogy. It's worth the wait - even if it doesn't answer all of the questions raised by the trilogy - it leaves room open for further development of this world.