Robert Frost's poem 'The Road Not Taken' explores the theme of choices in life, using the metaphor of a forked path in a yellow wood to symbolize the decisions we face. The speaker reflects on choosing the less traveled road, recognizing the irreversibility of choices and the adventures they lead to, despite feelings of regret. The poem employs various literary devices, such as metaphor, imagery, and simile, to convey deeper meanings about life's uncertainties and the impact of our decisions.