"Letters from the Earth" by Mark Twain is a posthumously published collection of essays written from the perspective of the archangel Satan. The essays were written in the late 1890s and early 1900s, but were not published until 1962 due to their controversial and irreverent content. In the book, Satan writes letters to his fellow angels in Heaven, commenting on various aspects of human life and religion. Through his letters, Satan presents a scathing critique of human morality, religion, and social norms, and highlights the contradictions and absurdities of human behavior. The book is a provocative and thought-provoking exploration of Twain's views on religion and humanity, and is often cited as one of his most controversial works. Despite its contentious nature, "Letters from the Earth" remains an important and influential work of American literature.