It is said that necessity is the mother of invention. But time is the driver of technological development. See how the inventions we use every day, from cars to cell phones, have evolved from their birth to today's technological advancements. A running timeline on each page makes this series perfect for supporting STEM topics in the elementary grades. Elementary readers will follow the sequence of how robots have changed from early automatons to today's autonomous delivery drones. Full-color photos and a running timeline illustrate important robotic breakthroughs. A table of contents, glossary, further resources, and an index are included.