Former Roanoke City mayor Nelson Harris is a local history buff for sure – he has just released his 12th book, this one entitled “A History of Back Creek,” which looks at other southwest county neighborhoods like Cave Spring, Poages Mill and Bent Mountain. One thing that struck Harris – how much the apple business meant to the area a century ago.Harris said he spent three years collecting old photographs from local residents for inclusion in the book. He will discuss “A History of Back Creek” and sign copies this Sunday at the South County Library on Merriman Road, at 2-pm.