Henry David Thoreau is known for championing the concept of civil disobedience in his writings, particularly in his essay titled "Civil Disobedience," published in 1849. In this work, he argues that individuals should refuse to comply with unjust laws and government actions, emphasizing the moral imperative to act according to one’s conscience. Thoreau’s advocacy for nonviolent resistance influenced various civil rights movements, notably that of Martin Luther King Jr. and Mahatma Gandhi. His ideas on the importance of personal integrity and social justice remain highly relevant in contemporary discussions about activism and ethics in relation to government authority.