The Visitor by Katherine Applegate

Rachel is still reeling from the news that the Earth is secretly under attack by parasitic aliens known as the Yeerks. And that she and her friends -- five kids who stumbled onto a downed spacecraft and were given the power to morph into any animal they touch -- are the planet's only defense. But Rachel has always been a daredevil. When it's suggested that they infiltrate the home of their assistant principal, who also happens to be a human host of the Yeerks, she volunteers. But what she finds inside may be more than even she can handle.

my first Animorphs read ever and I love Rachel!

Well I don't think I will be writing a review for ALL of these books because I think they'll pretty much have all the same pros and cons. This book was just as enjoyable as the last one. The only complaint I have is that the ending wasn't as epic as it was in the first book. I don't think I've ever read a series as long as this one that has a continuous plot (instead of being episodic) and the pacing seems like it might suffer a little but whatever. It's still all very fun to read.

Most disturbing thing from this volume: The taxxons eating each other alive while the one being eaten screams -shudder- Of course I don't doubt kids can handle this. I can picture a little boy reading this being like “heh heh sweeeet.” Me, it kinda creeps me out.