About two million years ago our ape-like ancestors in africa began to make tools by chipping flakes from pieces of flint. In so doing they took a gigantic leap forwards along the path to civilization. They had begun to invent things, a trait that set them apart from the other animals. They had begun to change their environment for their own benefit. And ever since human beings have been easing thier lives by making practical use of their discoveries and inventions---in other words , by techonology.