Recently, I had the opportunity to drive across North America, from Olympia, Washington, to New York City. September—after the heat of the summer is past and before the biting cold of winter has bared its teeth—was a wonderful time to take a trip this year. I particularly remember the vast, open spaces of the Valentine National Wildlife Refuge in north-central Nebraska, where I had an opportunity to clamber up a sand dune and chew the relentless wind that swept over the ocean of grass. With just the faintest imagination, immense bison herds replaced the quietly feeding cattle spotted across the landscape.