My excuse for writing this foreword is that I have been for thirty years a friend and adviser to Princeton University Press, helping to smooth the way for the huge and difficult project of publishing the Einstein Papers, a project in which Alice Calaprice has played a central role. After long delays and bitter controversies, the publication project is now going full steam ahead, producing a steady stream of volumes packed with scientific and historical treasures.

I knew Einstein only at second hand through his secretary and keeper of the archives, Helen Dukas. Helen was a warm and generous friend...