Down the Great Unknown By 1869, the last unexplored stretches of American landscape were the rocky, inhospitable areas carved out by the Colorado River. That year, an eccentric Civil War veteran assembled a rag-tag crew and set out to conquer the territory. Author Edward Dolnick says the quest, calls to mind Laurel and Hardy more than Lewis and Clark. Host Liane Hansen speaks with Dolnick about his new book, Down the Great Unknown: John Wesley Powell's 1869 Journey of Discovery and Tragedy Through the Grand Canyon. (published by Harper Collins; ISBN: 006019619X) To find out more, visit www.harpercollins.com/catalog/book_xml.asp?isbn=006019619X.