"Cherry Lake Press is an imprint of Cherry Lake Publishing Group"--Title page verso.
"21st Century Skills Library."
Audience
Ages 9-11 Cherry Lake Publishing.
Grades 4-6 Cherry Lake Publishing.
Summary
"The odds of us being alone in outer space are small. Maybe we've already been visited by alien life, but didn't even know it. What if those life forms are still here? Jump into some of Earth's most alien mysteries and explore the signs they may have left behind"-- Provided by publisher.
Bibliography
Includes bibliographical references (page 31) and index.
