How do we know so much about the animals or plants that lived millions of years ago? The answer is fossils! Fossils are prehistoric marks or remains that have been preserved in rock, gradually taking the form of bones and being replaced by minerals. Readers learn about the different types of fossils, the discovery of famous fossils and what we've learned from them, and so much more in this book. With eye-catching illustrations paired with achievable text, readers continue their curriculum studies outside of the classroom by diving into the study of fossils!