Daja's Book is about a girl, named Daja, who goes with her three mage friends and her teacher, Rosethorn, to try and help stop fires from spreading throughout the cities. This is the first time Daja ever comes to dislike fires, for she works with it (Daja is a metal-worker). While she is working with fire and trying to stop fire at the same time, Daja discovers a living metal vine. Then, some Traders come through the cities, and they bring back memories, for she used to be one herself. She is stuck deciding if she should continue on with her mage friends, or go with the Traders.
I would rate this book with four stars out of five, because I think that Tamora Pierce's other series are better than the Circle of Magic Series (including Daja's Book). Some of the events that happen in this book are a bit disappointing once you get to the end, and, unlike her other series, I don't think there is not as much adventure. Like her other books, though, there are good details, but perhaps a little too much, which makes it a tad more dull than the others. For example, on page 52, it says, "The lady wore a cloth-of-gold overrobe and a brown silk undergown with gold embroideries, both of which complimented her dark brown skin perfectly. The gold band on her brown, frizzy hair tilted up a little like a tiara and sparkled with emeralds; black pearls hung around her neck in three strand..." And so it continues. This is very good describing, but I think it is just a little too much than you need.
Other than that, if you have read all of Tamora Pierce's books, except for the Circle of Magic books, I'm not trying to stop you from reading any four of them, they are all good, otherwise I wouldn't have given Daja's Book four stars. Tamora Pierce is a great writer, and you should definitely consider reading one of her books, for she has several series out with four books in each series.
(I had to do this for an 11th grade school project, that's why I wrote so much!)