Gripping story line as well as educational about global warming with out feeling like its being forced on you, in fact you don't even realize that that is the point of the book until the last chapter your so fixated on the adventures these kids are running into in Antarctica. There is a small amount of violence but less then was in the first three books. The book is written in a way that children in 4th and 5th can easily read, and understand maturity of this book can be understood by some 2nd and 3rd graders and the content I feel would still be appropriate. I like the format that Patterson put his chapters in(same in all Maximum Ride series so far) it won't over whelm children who struggle with reading the longest chapter I believe was 10 pages long but usually averaged 4-5.