In 1945 I began to read for my doctorate at the Lebedev Institute, the department of physics in the Academy of Sciences of the USSR. My teacher there was the great theoretical physicist, Igor Evgenyevich Tamm.

He influenced me enormously and later became a member of the Academy of Sciences of the USSR and a winner of the Nobel Prize for physics. In 1947 I defended my thesis on nuclear physics, and in 1948 I was included in a group of research scientists whose task was to develop nuclear weapons. The leader of this group was I.E. Tamm.

For the next 20 years I worked under conditions of the highest security and under great pressure, first in Moscow and subsequently in a special secret research centre. At the time we were all convinced that this work was of vital significance for the balance of power in the world and we were fascinated by the grandeur of the task. In the foreword to my book Sakharov Speaks, as well as in My Country and the World, I have already described the development of my socio-political views in the period 1953-68 and the dramatic events which contributed to or were the expression of this development. Between 1953 and 1962 much of what happened was connected with the development of nuclear weapons and with the preparations for and realization of the nuclear experiments. At the same time I was becoming ever more conscious of the moral problems inherent in this work. In and after 1964 when I began to concern myself with the biological issues, and particularly from 1967 onwards, the extent of the problems over which I felt uneasy increased to such a point that in 1968 I felt a compelling urge to make my views public.

Peace, progress, human rights - these three goals are insolubly linked to one another: it is impossible to achieve one of these goals if the other two are ignored. This is the dominant idea that provides the main theme of my lecture. I am grateful that this great and significant prize, the Nobel Peace Prize, has been awarded to me, and that I have been given the opportunity of speaking to you here today. It was particularly gratifying for me to note the Committee's citation, which emphasizes the defense of human rights as the only sure basis for genuine and lasting international cooperation. I consider that this idea is very important; I am convinced that international confidence, mutual understanding, disarmament, and international security are inconceivable without an open society with freedom of information, freedom of conscience, the right to publish, and the right to travel and choose the country in which one wishes to live. I am likewise convinced that freedom of conscience, together with the other civic rights, provides the basis for scientific progress and constitutes a guarantee that scientific advances will not be used to despoil mankind, providing the basis for economic and social progress, which in turn is a political guarantee for the possibility of an effective defense of social rights. At the same time I should like to defend the thesis of the original and decisive significance of civic and political rights in moulding the destiny of mankind. This view differs essentially from the widely accepted Marxist view, as well as the technocratic opinions, according to which it is precisely material factors and social and economic conditions that are of decisive importance. (But in saying this, of course, I have no intention of denying the importance of people's material circumstances.)

There is a great deal to suggest that mankind, at the threshold of the second half of the twentieth century, entered a particularly decisive and critical period of its history.

Thermonuclear missiles, which in principle are capable of annihilating the whole of mankind, exist; this is the greatest danger threatening our age. Thanks to economic, industrial, and scientific advances, the so-called "conventional" arms have likewise grown incomparably more dangerous, not to mention chemical and bacteriological instruments of war.

There is no doubt that industrial and technological progress is the most important factor in overcoming poverty, famine, and disease. But this progress leads at the same time to ominous changes in the environment in which we live and the exhaustion of our natural resources. In this way mankind faces grave ecological dangers.

Rapid changes in traditional forms of life have resulted in an unchecked demographic explosion which is particularly noticeable in the developing countries of the Third World. The growth in population has already created exceptionally complicated economic, social, and psychological problems, and will in the future inevitably pose still more serious problems. In a great many countries, particularly in Asia, Africa, and Latin America, the lack of food will be an overriding factor in the lives of many hundreds of millions of people, who from the moment of birth are condemned to a wretched existence on the starvation level. In view of this, future prospects are menacing, and in the opinion of many specialists tragic, despite the undoubted success of the "green revolution".