Caroline Humphrey and Franck Billé are leading anthropologists who have spent years studying the border between Russia and China, a 2,600 mile-stretch that mostly follows the great Amur River. Their book, On the Edge: Life Along the Russia-China Border, describes how the regions on either side have developed in the context of the dramatic political and economic changes both countries have undergone in recent years. The book also takes a close look at the human relations — and separations — along the border, asking what they tell us about how these two great countries operate. Caroline Humphrey is a fellow of King’s College at the University of Cambridge, and founder of the university’s Mongolia and Inner Asia Studies Unit. Franck Billé is program director at the Tang Center for Silk Road Studies at the University of California, Berkeley. Caroline Humphrey.Illustration by Lauren Crow Q: Relations between the Russian and Chinese governments appear to have been getting clo