Asset stripping is sad. It means the parts are worth more than the whole, and that someone is going to sell those parts for profit. What if you apply this concept to a country? In Tate Britain’s Duveen Galleries, installation artist Mike Nelson has collected artifacts of British industry—rusty old symbols of postwar dreams and obsolete ideals—and sculpted them into a lost world. The English love an elegy and the critics are calling this one a masterpiece. —L.J.