This was a quick, fun read (it's YA, and it's Sanderson, so I guess that goes with the territory). As usual, Sanderson gives us characters we can cheer for, a well-thought-out magic system, and a slick plot that keeps us moving along with a few surprises along the way. It's also an intriguing world that Sanderson has built, often through little, casual details. The world appears to be a variant of our own, in a sort of steam-punkish-plus-magic sort of way, but with lots of little oddities. America is a whole lot of islands, on which were no native Americans when the Europeans showed up: instead, there were two-dimensional creatures called chalklings, made of--you guessed it--chalk. Which also happens to be the basis for a magic system in which Rithmatists draw geometric figures and little animate chalklings of their own. Europe was overrun by Japan (I think?), and as a consequence the British king fled to the Americas, which as a consequence are still a monarchy. 
 Anyway, the story revolves around Joel, who is not a Rithmatist even though he's obsessed with the subject. He attends a school where rithmatists and non-rithmatists are more or less educated side by side, leaving him oh-so-close but not one of them. However, when rithmatic students start disappearing under strange circumstances, Joel finds himself in the center of the effort to stop the abductions (or are they murders...?). 
 There's a bit of a Harry Potter-ish feel to the whole thing, in no small part because of the school for magic and a Snape-like professorial figure in the mix. It didn't feel derivative though, there were just certain elements that echoed pleasantly.