How to tell the difference between living and nonliving things--an essential first skill in scientific sorting and classifying--is explored with hands-on activities and colorful diagrams.

Kathleen Weidner Zoehfeld is the award-winning author of more than sixty books, including Dinosaur Tracks, "a great choice for even the most discriminating dinophiles" (School Library Journal); Did Dinosaurs Have Feathers?, a Children's Book of the Month Club selection described as "fascinating" by Kirkus Reviews; and Dinosaurs Big and Small, a 2003 Oppenheim Toy Portfolio Best Book Award winner. When she's not reading, researching, writing, or editing, Kathleen loves to spend her free time exploring, doing fieldwork, and preparing fossils in the laboratory for her local natural history museums. She lives in Berkeley, California.