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. This book for elementary readers describes the sequence of inventions that brought us from outdoor cesspits to today's smart toilets, complete with customized user settings. Engaging photos and a running timeline illustrate important ideas and inventions that have changed the way we dispose of our waste. A table of contents, glossary, further resources, and an index are included.