Mountain Interval is Frost's third published collection of poetry and is the first appearance of "The Road Not Taken." It also includes the poems "Christmas Trees," "In the Home Stretch," "Birches," "Snow," and "The Bonfire," among others. Throughout the volume, Frost grapples with how the choices of the past ultimately shape the future. "The Road Not Taken," the first and most famous poem of the collection, sets up this paradigm with the narrator's decision of which direction to take after reaching a fork in the road - a metaphor for decisions made along the road of life. While he had previously established his talent for verse with his first two poetry collections, Mountain Interval solidified Frost's status as a master poet.