Linda Formichelli is a freelance writer whose articles have appeared in several youth and science publications including Ack!, Delta Education, Odyssey, Yes, and Zillions. She is the author of Becoming a Personal Trainer for Dummies, Renegade Writer, and a coauthor of Tools of Timekeeping. W. Eric Martin has written articles for more than 50 publications and has provided dictionary entries for Thomson Gale's World of Computer Science. He is a coauthor of Tools of Timekeeping. They both live in Blackstone, Massachusetts. Sam Carbaugh is the illustrator of Amazing Math Projects You Can Build Yourself, Discover the Desert, Food: 25 Amazing Projects, George Washington: 25 Great Projects You Can Build Yourself, and Robotics." He lives in Grand Rapids, Michigan.