My favorite book is The Visitor by K.A. Applegate. It is the second book in her series called Animorphs. It's easy for me to pick a single book from the my favorite series to be my favorite book. Each book is narrated by one of the 5 main cast of teenagers, and The Visitor is the first book narrated by my favorite character Rachel and really defines her character for the rest of the series. In the book, Rachel struggles with the morality of war, her burning passion to fight for her friends, and her hope to live as a normal teenager. In The Visitor, Rachel infiltrates the home of her vice principal who is also being controlled by the yerks, the main villain of the series. Her best friend is also the vice principal's daughter. While she is in their home, morphed into their family cat, Rachel sees her friend struggle to connect with her parents, both of whom are being controlled by yerks. This ignites a fire in Rachel, and a turning point for her character; She becomes "Xena: Warrior Princess," as another Animorph calls her. Rachel's new passion causes her to make more and more dangerous gambles with her life in order to ease the suffering of her friend. Near the end of the book, Rachel and her cousin Jake (another Animorph) get captured to to Rachel not listening to the group and only caring about helping her friend. After she and Jake are rescued, Rachel has to come to terms with the fact that her friend's parents can't be saved right now. The book ends with Rachel trying to comfort her crying friend in the form of the family cat.