World War I explores the secrets of World War I. As in all wars, each side needed to keep secrets from the enemy. At the same time, they tried to discover the enemy's secrets, using spies and code-breakers.

This book provides a simple and fun introduction to fossils, discussing different kinds of fossils, exploring how and why they have formed, how they have changed over time, their appearance and properties. With the help of some Rock Solid! facts that provide cool examples, the book will show you how amazing fossils can be: from the prehistoric woolly mammoth body in Siberia and dinosaur remains to petrified forests.

How many countries are in North America? Where do bald eagles live? What language is spoken in Mexico? This book answers these questions and more as it introduces young readers to the continent of North America through age-appropriate maps, engaging photographs, and simple text. Topics covered within the book include where the continent is, climate, geography, animals and plants, countries, people and languages, natural resources, cities, and famous places.

This book provides a simple and fun introduction to minerals, discussing different minerals, exploring how and why they have formed, how they have changed over time, their appearance and properties. With the help of some Rock Solid! facts that provide cool examples, the book will show you how amazing minerals can be: from ruby crystals and stalagmites and stalactites in caves to talcum powder.

This book provides a simple and fun introduction to rocks, discussing different rocks, exploring how and why they have formed, how they have changed over time, their appearance and properties. With the help of some Rock Solid! facts that provide cool examples, the book will show you how amazing rocks can be: from the Grand Canyon and hot lava to the world’s biggest cave.

This book provides a simple and fun introduction to soil, discussing what soil is, how it is made and what we use it for. With the help of some Rock Solid! facts that provide cool examples, the book will show you how amazing soil can be: from making houses with mud bricks and how crops grow in volcanic soil to how tree roots can break up rock.

What is Europe's highest mountain? How many countries are in Europe? What languages do people in Europe speak? This book answers these questions and more as it introduces young readers to the continent of Europe through age-appropriate maps, engaging photographs, and simple text. Topics covered within the book include where the continent is, climate, geography, animals and plants, countries, people and languages, natural resources, cities, and famous places.

This book looks at batteries, examining what they are, the different types of batteries, and how we use them. The book considers a range of examples that will be familiar to young readers, and explains the scientific concepts behind batteries and electricity in clear, simple language.

Did you know that all gadgets and games have a life cycle? That's what we call the stages from their design, manufacture, and sale to their use, maintenance, and disposal. This book explains what happens during these stages, such as prototyping, the sourcing of components, the production process, the decisions made by designers and engineers, and recycling.

Do you know that computers were only invented within the past 100 years? And that the smartphone was only recently invented, in the mid-1990s? Yet today, computers and other devices are everywhere in our lives--in classrooms, homes, and public places. From the first calculating machines made of cogs and wheels during the 1640s to virtual reality headsets such as Oculus Rift, this book charts the incredible history of computers.

Did you know that the wheel was invented in prehistoric times, in about 3500 B.C.? Now we can travel between towns and cities in super-fast trains, in fast cars, and halfway around the world in a day in airplanes. From dugout canoes from 10,000 years ago right through to modern-day driverless cars, this book charts the amazing history of transportation.

Where is the Sahara Desert? What is Africa's highest mountain? Where do elephants live? This book answers these questions and more as it introduces young readers to the continent of Africa through age-appropriate maps, engaging photographs, and simple text. Topics covered within the book include where the continent is, climate, geography, animals and plants, countries, people and languages, natural resources, cities, and famous places.