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 how (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.

In the beginning, the planet upon which we live was (as far
as we now know) a large ball of flaming matter, a tiny cloud of
smoke in the endless ocean of space. Gradually, in the course
of millions of years, the surface burned itself out, and was covered