Prehistory refers to the time period before the invention of writing. 

The term prehistory is derived from two words: pre, which is from a Latin word meaning before and history which is a record of human events. 

Prehistoric life refers to all things that lived on Earth before people learnt how to write, hence there are no written records.

Finding out about prehistory is done by a special group of people known as paleo-scientists. They are like time-travelling detectives who help us unlock mysteries of the past. They study special clues such as fossils and artefacts left behind from a long time ago.