“The Continental Divide Trail: Exploring America’s Ridgeline Trail,” by Barney Scout Mann (Rizzoli) What makes America great is not necessarily its constitution nor its entrepreneurial spirit, writes Pulitzer Prize-winning author Nicholas Kristof in his introduction to “The Continental Divide Trail.” “Another element of American exceptionalism is the beauty and sweep of our public lands.” That is evident in a selection of Christmas books about the West. The Continental Divide has intrigued Americans since the pioneers, who saw it — like the Mississippi and Missouri rivers — as a way of separating East from West. It was not until 1978, however, that Congress designated it as a national scenic trail. In 2015, photographer Barney Scout Mann hiked the trail, photographing the land, the people, the wildlife and flowers.