The Undersea World (A True Book: Greatest Discoveries and Discoverers)

Though explorers have been searching Earth's deepest waters for many years, experts estimate that we have explored only about five percent of the global ocean.

Readers (Grades 3-5) will learn about the history of deep-sea exploration, from the creation of the earliest submersibles to today's high-tech expeditions to the planet's deepest points. They will also find out what we've discovered underwater so far and what lies in store for the future of deep-sea exploration.

Tamra B. Orr is the author of "After Homeschool," "The Parents' Guide to Homeschooling," "The Purple Cow Guide to Extraordinary Essays," and "Violence in Our Schools," She lives in Portland, Oregon.