Montana has been the "last best place" for so many people. A century ago, Native Americans gathered here to perform the Ghost Dance—a last, doomed attempt to make white settlers vanish and bring back the old ways of life. Today, people are still pouring into Montana, looking for the pristine wilderness they saw in A River Runs through It.

The reality of Montana—indeed, of all the West—has never matched the myths, but this book eloquently explores how the search for a perfect place is driving growth, development, and resource exploitation in Big...