Letters from the Earth

In 1962, more than fifty years after Mark Twain’s death, his daughter finally allowed the publication of the essays and satirical short stories that were deemed too irreligious and controversial to see the light of day when he wrote them. The pieces were gathered by Twain’s literary executor Bernard DeVoto in a collection titled "Letters from the Earth", and they feature sharp takes on the inconsistencies and illogic of Christianity and biting criticisms of American life.

"Letters from the Earth" is a collection of essays that were written during a difficult time in Twain's life; he was deep in debt and had lost his wife and one of his daughters. The book consists of a series of short stories, many of which deal with God and Christianity. Twain penned a series of letters from the point-of-view of a dejected angel on Earth. This title story consists of letters written by the archangel Satan to archangels, Gabriel and Michael, about his observations on the curious proceedings of earthly life and the nature of man's religions. 
By analysing the idea of heaven and God that is widely accepted by those who believe in both, Twain is able to take the silliness that is present and study it with the common sense that is absent. Not so much an attack as much as a cold dissection. 

Other short stories in the book include a bedtime story about a family of cats Twain wrote for his daughters, and an essay explaining why an anaconda is morally superior to Man. 

Twain's writings in "Letters from the Earth" find him at perhaps his most quizzical and questioning state ever.