In one sense, Dave Eggers’s Heroes of the Frontier is a very recognizable novel—the ingenue in the new wilderness, trying to make sense of, and being buffeted about by, this brave new world. But Heroes is also a uniquely modern take on the old frontier genre: It is a fable without a moral, a pilgrim without progress, a series of adventures and nothing to be made of them. There are some real pleasures here but, for me, this book is interesting as much for what it includes as for what it leaves out.