Every document in The Collected Papers of Albert Einstein appears in
the language in which it was written, and supplementary paperback
volumes present the English translations if all non-English materials.
For those desiring a supplement to Volume 5, for instance, this
paperback includes translations of correspondence that give a much
richer picture of Einstein in his twenties and thirties than we ever
had. In addition to illuminating the personal aspects of his life, the
letters document his scientific activity: his concentration for years on
the unfathomable problems of quanta and radiation, his extensive
knowledge of experimental physics, his many fruitful interactions with
experimentalists, and finally his long struggle to generalize the 1905
theory of relativity to include gravitation and accelerated frames of
reference. This paperback translation does not include notes or
annotation of the documentary volume and is not intended for use without
the original language documentary edition, which provides the extensive
editorial commentary necessary for a full historical and scientific
understanding of the documents.