Michael Harker drove past old barns on gravel roads and blacktop highways for years. He generally dismissed them as obsolete outbuildings until November 1993, when he felt compelled to photograph a windmill in Clutier, Iowa. This single photograph launched him on a seven-and-a-half-year mission to document Iowa's barns and all they represent. The result is Harker's Barns: Visions of an American Icon. Each of the seventy-five black-and-white...