Then the song of a whitethroat, pure and ethereal, with the dreamy quality of remembered joy.

To understand the living present, and the promise of the future, it is necessary to remember the past.

Along with the possibility of extinction of mankind by nuclear war, the central problem of our age has therefore become the contamination of man's total environment with such substances of incredible potential for harm-substances that accumulate in the tissues of plants and animals and even penetrate the germ cells to shatter or alter the very material of heredity upon which the shape of the future depends.

The human race is challenged more than ever before to demonstrate our mastery, not over nature but of ourselves.

We still talk in terms of conquest. We still haven't become mature enough to think of ourselves as only a tiny part of a vast and incredible universe. Man's attitude toward nature is today critically important simply because we have now acquired a fateful power to alter and destroy nature. But man is a part of nature, and his war against nature is inevitably a war against himself.

When we go down to the low-tide line, we enter a world that is as old as the earth itself - the primeval meeting place of the elements of earth and water, a place of compromise and conflit and eternal change.

Only within the moment of time represented by the present century has one species -- man -- acquired significant power to alter the nature of the world.