"In 1978 China initiated a change that not only altered its own course but was to have a profound effect on the world. We have long known that it began when Deng emerged as China's preeminent leader and launched the era of reform and opening, but we have known little about the 34-day Party Work Conference that started on November 10 1978. We have also known little about what went on behind the scenes at the Third Plenum (of the 11th Party Congress) that began immediately after, on December 18.
"Fortunately for historians, in 1998 on the 20th anniversary of these events, one of the last remaining key participants in these meetings, Yu Guangyuan, then age 83, wrote a book describing the background and the contents of both meetings]. Yu was a regular participant in the Party Work Conference. Although he was not a member of the Central Committee, he had attended the plenum as a staff member and took regular notes. Yu based his book on detailed notes he had taken at these meetings.
"...Thanks to Yu's account, we now understand the nature of the Party Work Conference and the drama that took place there. Until Yu's book appeared, it was possible for Western scholars to argue that the turning point in reform and opening was at the Third Plenum of December 1978. We now know that the key debates were held at the 34-day Party Work Conference ... and that the Third Plenum which followed immediately was essentially ceremonial, officially approving the new consensus worked out at the Party Work Conference."
--From the Introduction by Ezra F. Vogel