In this novella, rivers have several meanings. On one level, a river represents the natural world. On another level, the arc of a river flowing through the rocks and canyons of Montana symbolizes the arc of a human life. Both meanings of the river inform the overarching structure of the novella.

It is also significant that there are so many rivers named in the story: the Big Blackfoot, the Elkhorn, the Swan, the Missouri, Clark Fork, and other specific canyons or places on these rivers. Each river is a specific terrain and contains specific types of trout that require specific techniques and know-how. Maclean explains each river in detail, demonstrating that he is striving to master the language of the rivers and the fish in order to understand the river and life itself.

Part technique, part art, and difficult to master, fly fishing, its terminology and its methods permeate this novella. Detailed descriptions of the rod, the different flies used according to the weather, the river and the type of trout being sought, entwine with Maclean’s philosophical explorations of the meditative and spiritual dimensions of fishing. Fly fishing becomes an extended metaphor for man’s approach to life.