For over two hundred years, scientists have been experimenting on ways to measure hot and cold. One problem was where to start. How cold is the coldest cold?

Dr. Asimov introduces us to Fahrenheit, who made the first thermometer, Kelvin, Celsius, and other scientists whose names are familiar even today.

As we follow their explorations of temperature, the story becomes an adventure, because they found an answer to a question that hadn't even been asked. They discovered that at a very, very low temperature, certain materials could transfer energy with no resistance at all!

This exciting “accidental” discovery may change the way we all work and live.

This book might be better titled How Did We Find Out About Absolute Zero?, since it’s only with the last chapter that superconductivity is discussed. But that’s a quibble. Beyond that, there’s little to say, however—it’s a solid member of the How Did We Find Out series, a good introduction to younger people to a particular area of physics, but perhaps a little boring for someone older. The illustrations are a bit weaker than usual, perhaps, too.