Katherine A. 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 are the planet's only defense....

The Earth is being invaded, but no one knows about it. When Jake, Rachel, Tobias, Cassie, and Marco stumble upon a downed alien spaceship and its dying pilot, they're given an incredible power - they can transform into any animal they touch. With it, they become Animorphs....

Elfangor-Sirinial-Shamtul is an Andalite war prince--the one who gave the Animorphs the power to morph. "The AndaliteChronicles" is the story of how this warrior-cadet ended up on planet Earth.

What's tasty, good for you, and only takes 60 seconds to make? Oatmeal. And because of a strange reaction to the Yeerk's physiology, it's making the would-be invaders of Earth more than a little crazy....

When Tobias and his friends were given the power to morph, they were also given an important warning: Never stay in a morph for more than two hours. But Tobias broke the time limit, and now he's trapped in the body of a hawk - forever....

There's been an accident. Someone crash landed a Yeerk Bug fighter, and the Yeerks have been trying to cover it up - quickly. When Tobias spots it before they get the chance, the Animorphs decide to steal the ship, to show the world that Earth has been invaded....

Dak Hamee is a unique Hork-Bajir. His people call him a seer. He learns more quickly and completely than the rest of his docile race. Hork-Bajir like him are born once a generation.

Tobias's worst nightmare has come back to haunt him-Taylor. Taylor is the evil Yeerk that captured and tortured Tobias, trying to get him to reveal the secrets of the Animorphs. Now she's captured him again-but this time, she wants his help.

We found out who Visser Four is. And he has found the Time Matrix, the machine Elfangor had hidden in the abandoned construction site. The same place we met him on a night none of us will ever forget. Especially me. Now Visser Four has the Matrix, and he plans to use it to become Visser One....

Cassie's had it. After the last mission, she realizes she's getting tired of missions. Tired of battles. Tired of being an Animorph. She decides that she just can't do it anymore. So she quits. But the war for her planet isn't so easy to quit....

We could blame everything that happened on Marco. He was the one who heard about the downed submarine. He was the one who thought we should check it out. And everyone knows that if Marco's up to a challenge, I'm definitely there.

Jake's made an amazing discovery. There may be other people who know about the alien invasion of Earth. Others who know about the Yeerks. Jake finds a website devoted to revealing the existence of the Yeerks, but he and the other Animorphs suspect it might be too good to be true....

The Yeerks aren't playing around anymore. They're no longer hiding behind a silent invasion. And one of the first steps in their new plan is to take over the National Guard, to prepare for all-out war against humanity.

Author Katherine Applegate’s stories about Roscoe Riley are popular with young readers who know what it’s like to get into trouble—accidentally....

Ax and the Animorphs are about to have a huge problem. It starts when they decide to morph into mosquitoes in order to slip by some unsuspecting Yeerks, and ends with them stuck in Zero-space with no idea how they got there, no way back to Earth...and no oxygen....

It seems everyone is winning trophies lately - except Roscoe. A dog trick contest could turn things around, but Roscoe's goofy dog can't learn any neat tricks....

Ax is an Andalite, an alien, stranded on a strange planet he's sworn to defend, even though it's not his own. Since the Animorphs rescued him, he's fought at their side, and in that time they've come to consider Ax a friend. But deep inside, Ax knows he isn't their friend....

The last time Rachel and her friends entered the giant Yeerk pool beneath their town things went very bad. This time they plan to be careful, and sneak in as roaches, just to spy. Once they're inside, though, the team gets caught....

Tobias has gotten used to his new life. He's a red-tailed hawk with the mind of a kid. It was difficult when he first became trapped in his morph, but he's started to come to terms with things....

Things were already really weird. Fighting aliens. Battling to have Earth. And still trying to be normal. Marco and the other Animorphs are almost used to it. But things are changing. The Yeerk invasion of Earth started out passively, secretly.