It has been said that no man is irreplaceable. Like most generalizations, this one too is not entirely correct. The passing of Albert Einstein, in Princeton, N. J., on April 18, 1955, certainly was an irreplaceable loss to science, to scholarship, to humanitarianism, to the cause of peace, and to the conscience of mankind. For, if the conscience of humanity could ever be said to have been represented by one single living human being, that human being was the great and truly immortal Einstein. To the editor of this LIBRARY Einstein's passing was also a great personal loss. My numerous visits and personal conversations with him constitute an indescribable legacy and indestructible memory of the greatest human being it has ever been my privilege to know personally.
Since the present ( third) edition of our Einstein volume is the first one to be released since Einstein's even yet untimely passing, the editor felt deeply obliged to say at least that much. But all of us are pleased to know that this volume is, at long last, available again.
After all, this volume contains the only thing even so much as approximating an Autobiography that the great Einstein ever wrote. And this appears both in the great scientist's original German and in English translation, side by side and page by page (for all of 95 pages). This, by itself, is an imperishable document, which is even more significant precisely because it contains much more of Einstein's scientific thought- development than it does mere matters of personal recollection. His "Reply to Criticisms" is equally important and of permanent significance.
This third edition has been (1) corrected for errors, and (2) brought more nearly up-to-date in the Bibliography. We know that it will receive the same enthusiastic reception which greeted the first two editions of this--in a real sense timeless--volume.
The editor wishes to express his appreciation to the new