Diadem #2: Book of Signs, by John Peel
"Book of Signs" continues the adventures of Score, Helaine, and Pixel, who were first introduced in "Diadem #1: Book of Names." Having defeated their first enemy, the trio has traveled to another world in the Diadem, the world of Rawn.
On Rawn, they encounter some of the typical races who inhabit fantasy lands: goblins, trolls, and centaurs. The three are still learning to work together and how to use their magic powers, including the use of gemstones to augment their abilities. They learn the power of teamwork as they journey through Rawn, intent on finding the sorceress of the world.
The story is a little simplistic at times, but granted, this series is aimed at younger readers in the 9-12 range. I think what's great about the Diadem series is that it promotes working together, rationality, intelligence, and tolerance as Score, Helaine, and Pixel befriend the goblins, which benefits them much more than if they had tried to kill the goblins.
If you're an adult or teenager checking out the Diadem series, I recommend you read the first three books all together, as they are a larger story and each ends in a cliffhanger.
4/5.