Briar's Book by Tamora Pierce

This final book in Tamora Pierce's Circle of Magic quartet shows with wonderful clarity Pierce's ability to have her books grow up with her characters (the Circle Opens, which chronologically follows these books, shows this even further). As the perspectives of Sandry, Briar, Tris and Daja deepen with experience and maturity, so Tamora Pierce's fictional land of Emelean seems colored more thoroughly in grays rather than only blacks and whites. 

In this book, which is primarily concerned with the outbreak of a plague and the characters' attempts to control and cure it, the lives of the adult characters are further revealed, and readers older than the books intended audience may be glad to see that Pierce devotes just as much attention to their characterization as she does to that of her younger protaganists. For me, the concerns of Lark, Rosethorn, and Crane were just as involving as those of the younger characters, and sometimes more so. Though this book is ostensibly centered around Briar, and it is true that the main conflict concerns his character arc, due attention is still paid to the other characters. A satisfying conclusion to a very nice quartet, and one that will leave readers excited to read further installments set in this world.