From the wheel to the telephone to the Walkman, meet the men & women behine these inventions. Meet the people who made weapns out of sticks & stones, to the masterminds of the computer age, trace the history of technologcal developments. Discover the origin of the railroads, calculators & space shuttles. How is your voice transmitted through telepoone wires? How do lasers save lives? Find the answers in the Usborne Bookof Inventors. A great, informative book.