I remember them well and read many of the National Geographic articles, and a book or two. As a kid we visited the National Geographic headquarters in Wash. DC, and they (the Society, not the brothers) were showing their Craighead episode on Grizzlies.
Much later I learned that a book I read as a child while living in the "concrete jungle," which would change my life, "My Side of the Mountain," was written by their sister, Jean Craighead George.
Much of who I am today interest-wise can be traced to that family. I too would like to know what became of, or has become of them.
