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]