Henry David Thoreau (1817–1862) was an American essayist, poet, and philosopher, and a key figure in the transcendentalist movement. He is best known for his book “Walden,” a reflection on simple living in natural surroundings, and his essay “Civil Disobedience,” which argues for individual resistance to unjust government policies. Through his writings, Thoreau advocated for a life of simplicity, environmental stewardship, and personal integrity. His ideas on civil disobedience influenced prominent leaders such as Mahatma Gandhi and Martin Luther King Jr., and his work continues to resonate with those interested in ecology, philosophy, and social justice.