Volume 16 is currently expected to cover the period of June 1927 to May 1929 and present as full text some 90-100 writings by Einstein and 500 letters written by and to Einstein. Approximately 1,200 additional documents will be presented in abstract. This period witnesses the beginning of Einstein’s intense preoccupation with a new approach to a possible unified field theory. The volume will include many family letters documenting an episode of severe declining health for Einstein. In spring 1929, Einstein’s mailbox is flooded with congratulatory letters and messages for his 50th birthday, to which he feels obliged to answer.