This is a short novella with only a handful of characters and a straightforward plot. Despite this, Sanderson manages to create a sense of mystery to the Aviar, the islands, and the Ones Above that drives the story. As always, Sanderson is a master of magic and he provides some partial, yet fulfilling, answers to how the magic of this world works. The book ends rather open-ended, letting the reader imagine what will happen in the future. Some of the secrets also spark my curiosity (ie, why Aviar and not humans?). I hope that Sanderson revisits the First of the Sun world as it sounds very cool (a distinct Polynesian vibe) and feels like the magic could be more fleshed out. 
 A full, but still short, review can be found in my blog: http://strakul.blogspot.com/2014/11/b...