A Single Pebble — John Hersey

A young American engineer sent to China to inspect the unruly Yangtze River travels up through the river's gorges searching for dam sites. Pulled on a junk hauled by forty-odd trackers, he is carried, too, into the settled, ancient way of life of the people of the Yangtze -- until the interplay of his life with theirs comes to a dramatic climax.