My 12-year-old son is an avid reader and I'm often asked for recommendations from parents who wish their kids read more and/or who struggle to find a book that's as compelling as their phone/XBox/any electronic device.
Note: The Boy gravitates towards action/adventure, science fiction or fantasy. There are tons of other books out there and this list isn't comprehensive but, for what it's worth, these books were unputdownable. Also, most of these are YA vs. MG, so there may be some language, etc. A great place to get info on suggested age appropriateness is Common Sense Media.
The first in a 3-book series. Sanderson is a popular author of adult fantasy and judging by the way The Boy devoured this series, his foray into YA is just as popular.