1 THE SETTING OF THE STAGE

We live under the shadow of a gigantic question mark.

Who are we?

Where do we come from?

Whither are we bound?

Slowly, but with persistent courage, we have been pushing this question mark further and further towards that distant line, beyond the horizon, where we hope to find our answer.

We have not gone very far.

We still know very little but we have reached the point where（with a fair degree of accuracy）, we can guess at many things.

In this chapter I shall tell you bow（according to our best belief）the stage was set for the first appearance of man.

If we represent the time during which it has been possible for animal life to exist upon our planet by a line of this length, then the tiny line just below indicates the age during which man（or a creature more or less resembling man）has lived upon this earth.

Man was the last to come but the first to use his brain for the purpose of conquering the forces of nature. That is the reason why we are going to study him, rather than cats or dogs or horses or any of the other animals, who, all in their own way, have a very interesting historical development behind them.