Almost no one in the West had heard of the Hmong before National Geographic ran a cover story on the Southeast Asian ethnic group that had allied with the United States in the Vietnam War, and few knew of them before their arrival in the U.S. and other Western nations in 1975. Originating in China centuries ago, they have been known by various names--Miao, Meo, Miaozi, Meng or San Miao--some of them derogatory. The Hmong in...