Afghanistan saw 4 million of its refugees flood back into the country after the Taliban government fell in 2001. Some are still suffering. Others are still returning. And that prompted best selling novelist Khaled Hosseini to lend his literary celebrity to the cause. The author of The Kite Runner and A Thousand Splendid Suns returned to Afghanistan for the first time since those novels came out. As a good will envoy for the U.N. High Commissioner for Refugees, Hosseini traveled to Kabul and the countryside around it. He speaks with Renee Montagne.