British Airships: Past, Present and Future

First published before the invention of airplanes, this book focuses on lighter-than-air craft. It begins: "Lighter-than-air craft consist of three distinct types: Airships, which are by far the most important, Free Balloons, and Kite Balloons, which are attached to the ground or to a ship by a cable. They derive their appellation from the fact that when charged with hydrogen, or some other form of gas, they are lighter than the air which they displace. ”