From this experience emerged Walden, one of the great classics of American literature, and a deeply personal reaction against the commercialism and materialism that Thoreau saw as the main impulses of mid-19th-century America. Here also is Civil Disobedience, Thoreau’s essay on just resistance to government, which not only challenged the establishment of his day but has been used as a flag for later campaigners from Mahatma Ghandi to Dr Martin Luther King.