rovide as well the basic background
facts necessary for informed perspectives on the issue.

New discoveries have been made, yet much uncertainty inevitably
persists. Our knowledge of nuclear warfare rests largely on theory and
hypothesis, fortunately untested by the usual processes of trial and
error; the paramount goal of statesmanship is that we should never
learn from the experience of nuclear war.

The uncertainties that remain are of such magnitude that of themselves
they must serve as a further deterrent to the use of nuclear weapons.
At the same time, knowledge, even fragmentary knowledge, of the broader
effects of nuclear weapons underlines the extreme difficulty that
strategic planners of any nation would face in attempting to predict
the results of a nuclear war. Uncertainty is one of the major
conclusions in our studies, as the haphazard and unpredicted derivation
of many of our discoveries emphasizes. Moreover, it now appears that a
massive attack with many large-scale nuclear detonations could cause
such widespread and long-lasting environmental damage that the
aggressor country might suffer serious physiological, economic, and
environmental effects even without a nuclear response by the country
attacked.

An effort has been made to present this paper in language that does not
require a scientific background on the part of the reader.
Nevertheless it must deal in schematized processes, abstractions, and
statistical generalizations. Hence one supremely important perspective
must be largely supplied by the reader: the human perspective--the
meaning of these physical effects for individual human beings and for
the fabric of civilized life.

Fred C. Ikle
Director
U.S. Arms Control and Disarmament Agency

INTRODUCTION

It has now been two decades since the introduction of thermonuclear
fusion weapons into the military inventories of the great powers, and
more than a decade since the United States, Great Britain, and the
Soviet Union ceased to test nuclear weapons in the atmosphere. Today
our understanding of the technology of thermonuclear weapons seems
highly advanced, but our knowledge of the physical and biological
consequences of nuclear war is continuously evolving.

Only recently, new light was shed on the subject in a study which the
Arms Control and Disarmament Agency had asked the National Academy of
Sciences to undertake. Previous studies had tended to focus very
largely on radio