This book introduces readers to the microscopic world of Earth's tiniest invertebrates. Young readers will enjoy fun facts about roundworms and tardigrades, and get up-close-and-personal with their incredible resilience, adaptive abilities, and unique characteristics. Vibrant illustrations and photographs help bring the text to life. Other features include a table of contents, an activity or craft, a phonetic glossary, infographics, sources for further research, information about the author, and critical-thinking questions to help readers connect with the text.