The work of Henry David Thoreau is well-known for its emphasis on naturalism and self-reliance, particularly in his famous book "Walden." Thoreau's philosophy revolves around the idea of living in harmony with nature, advocating for simplicity, and emphasizing individualism. His belief in self-reliance encourages people to trust their instincts and capabilities, rather than conforming to societal pressures. Thoreau's writings reflect his values of independence and the importance of personal experience, making him a central figure in the transcendentalist movement, which heavily influenced American thought in the 19th century.
In contrast, other authors mentioned have different focuses. Machiavelli is primarily concerned with political theory and power dynamics, while Elie Wiesel's work centers around themes of survival and morality in the context of the Holocaust. Booker T. Washington's writings often address issues of education, race relations, and economic development within the African American community. These differing themes highlight the unique focus of Thoreau on individualism and nature, underscoring why he is the correct choice for this question.