As a chief interpreter for Nixon's 1972 ice breaking trip to China, American senior diplomat Chas W. Freeman was a witness to the normalization of China-U.S. ties when the Shanghai Communique was signed. Recent years have witnessed the world's most critical relationship nosedive to a dangerous point. What are his observations of the ups and downs of China-U.S. ties over the past half a century? What are his suggestions for dealing with the challenges facing these two countries? And how could these two big powers cooperate for the sake of global governance?