China is so big, diverse and protean that no single photograph can sum it up. And yet iconic images often come to represent the country at a particular point in time, the way the-man-who-stopped-the-Tiananmen-tanks did in the late 1980s. Michael Meyer’s impressive new book, “The Last Days of Old Beijing: Life in the Vanishing Backstreets of a City Transformed” (Walker & Co. 368 pages), goes a long way toward illuminating some of the scenes that have come to symbolize early-21st-century China, at least before the unrest in Tibet and the Sichuan earthquake. They include wrecking balls knocking down beloved small businesses; schoolchildren dragging their migrant-worker parents, who have never been in a restaurant, into a KFC; human-powered vehicles in a land of high-rises, evoked by the canopied pedicab set against construction cranes, as depicted on the book’s cover.