Harrigan's deceptively straightforward voice belies an intense curiosity about things that, by his own admission, may be "unknowable." Certainly, we are limited in what we can know about the inner life of George Washington, the last days of Davy Crockett, the motives of a caged tiger, or a father we never met, but Harrigan's gift—a gift that has also made him an award-winning novelist—is to bring readers closer to such things, to make them less remote, just as a cave painting in the title essay eerily transmits the living stare of a long-extinct mammoth.