Every weekday, Mr. Wang says goodbye to his daughter and his beloved pigeons in an old-fashioned Beijing neighborhood, mounts his bicycle and ventures into the chaos of the city.

His destination is a local post office, where he parks his bike and climbs into a green express mail van.

Over the last 12 years, Mr. Wang (known as Laowang, or “Wang the Elder”) has picked up perhaps a quarter of a million packages destined for dozens of countries. Does he ever wonder what’s in those packages? Or who will receive them on the other end? Or why there’s such a big rush?

“No,” he says, “I just want to make some money!”