A satellite is a small object traveling around something bigger. The Moon is a natural satellite of Earth. A spacecraft launched into orbit around Earth is an artificial satellite.

Robots are machines that can be programmed to carry out a series of complex actions automatically or under the control of an operator. They come in all shapes and sizes, from mechanical arms and driverless vehicles to walking, talking, artificial people.

"For thousands of years, nurses have tended to the sick and the wounded. Although they don't get the glory, nurses are just as important as doctors. Read all about the eventful history of nursing and marvel at how nurses today take care of us in the hospital or at home, comfort relatives, cheer us up when we have to stay in bed, and help us make a complete recovery,"--back cover.