The Born-Einstein letters

The relativity and quantum theories, the theoretical foundation of modern physics, are generally held to be abstract systems of ideas, inaccessible to the layman, which no longer show much evidence of their human origin. It is, however, the human aspect of the developing science, more than anything else, which this correspondence between Albert Einstein and Max Born renders intelligible. Einstein and Born were both in the front rank of those who contributed towards the formation of modern physics. In the year 1916, at the beginning of the correspondence, Einstein had just completed his papers about the general theory of relativity, and was concentrating his efforts on the then still very puzzling quantum phenomena. During the years which followed Born, together with his pupils in Gottingen, took a number of decisive steps which led to an understanding of these very phenomena. Nothing demonstrates more clearly the exceptional difficulties which stood in the way of a clearer understanding of atomic phenomena - in spite of the considerable amount of experimental data already obtained - than the fact that these two scientists, who on the human level were on such intimate terms, failed to agree about the final interpretation of the quantum theory. But their correspondence does not merely bear witness to the dramatic argument about the correct interpretation of atomic phenomena. It also shows the way in which human, political and ideological problems are intermingled in this discussion, and for this reason the contemporary history of the years 1916 to 1954 plays an important part in these letters. [from Heisenberg's Preface]