Conor Knighton is a correspondent for CBS Sunday Morning and the author of a wonderful, just published book called "Leave Only Footprints: My Acadia-to-Zion Journey Through Every National Park". We devoted the entire show to the book, talking with Conor about the history of a number of the parks, oddities and mysteries that can be found in some of them, and Conor's very personal reasons for undertaking this year-long quest (hint: it involves getting dumped right before his wedding).