The Encyclopaedia Britannica Interactive Science Book: Earth is an 80-page, brilliantly illustrated book for people of all ages designed for use with the SD-X Interactive Reader (sold separately). The book is part of a six-book library. The books are available separately and also are sold in sets of three and a set of six.The SD-X Interactive Reader is a battery-powered pen that reads text on the book pages and also offers audio content such as facts and sound effects. The Reader works only with the six Encyclopaedia Britannica Interactive Science Library books. Each book has two hours of audio content.The Encyclopaedia Britannica Interactive Science Book: Earth covers more than 4.6 billion years of the earth's history, starting with a chapter on the earth's formation that traces the evolution of the landscape and seascape we live on today. The book also covers rocks and minerals, volcanoes, earthquakes, tsunamis, weather, and climate. The book looks at the physical wonders of the planet from every angle—all accessible in an enhanced format using the SD-X Interactive Reader. - from Amzon