Before magnifying glasses, how did people make objects look larger? The ancient Romans filled glass bowls with water. Then microscopes and telescopes came along. But optical innovation didn't stop there. Learn how many lightbulb designs Thomas Edison tested, how spies used microfilm to carry secret messages, how satellites let us look at Earth from space, and more! Fact-packed text and fun illustrations reveal crazy inventions (spectacles for horses!) and offbeat predictions (some people thought electric light would never catch on). Follow the trail of inventions and devices that have enabled us to see everything from distant stars to tiny cells.