Title: Mark Twain
Content:  Twain was a Presbyterian. He was critical of organized religion and certain elements of Christianity through his later life. He wrote, for example, "Faith is believing what you know ain't so", and "If Christ were here now there is one thing he would not be – a Christian". With anti-Catholic sentiment rampant in 19th century America, Twain noted he was "educated to enmity toward everything that is Catholic". As an adult, he engaged in religious discussions and attended services, his theology developing as he wrestled with the deaths of loved ones and with his own mortality. Twain generally avoided publishing his most controversial 
Title: Mark Twain
Content:  particularly and in all other Christian countries in a somewhat modified degree – it is still a hundred times better than the Christianity of the Bible, with its prodigious crime – the invention of Hell. Measured by our Christianity of to-day, bad as it is, hypocritical as it is, empty and hollow as it is, neither the Deity nor his Son is a Christian, nor qualified for that moderately high place. Ours is a terrible religion. The fleets of the world could swim in spacious comfort in the innocent blood it has spilled." Twain was a Freemason. He belonged to Polar Star Lodge 
Title: Mark Twain
Content:  on religion in his lifetime, and they are known from essays and stories that were published later. In the essay Three Statements of the Eighties in the 1880s, Twain stated that he believed in an almighty God, but not in any messages, revelations, holy scriptures such as the Bible, Providence, or retribution in the afterlife. He did state that "the goodness, the justice, and the mercy of God are manifested in His works", but also that "the universe is governed by strict and immutable laws", which determine "small matters", such as who dies in a pestilence. At other times, he plainly professed a 
Title: Mark Twain
Content:  79 A.F.&A.M., based in St. Louis. He was initiated an Entered Apprentice on May 22, 1861, passed to the degree of Fellow Craft on June 12, and raised to the degree of Master Mason on July 10. Twain visited Salt Lake City for two days and met there members of The Church of Jesus Christ of Latter-day Saints. They also gave him a Book of Mormon. He later wrote in Roughing It about that book: "The book seems to be merely a prosy detail of imaginary history, with the Old Testament for a model; followed by a tedious plagiarism of the New Testament."
Title: Mark Twain
Content:  Joan of Arc best of all my books, it is the best". Those who knew Twain well late in life recount that he dwelt on the subject of the afterlife, his daughter Clara saying: "Sometimes he believed death ended everything, but most of the time he felt sure of a life beyond." Twain's frankest views on religion appeared in his final work Autobiography of Mark Twain, the publication of which started in November 2010, 100 years after his death. In it, he said: "There is one notable thing about our Christianity: bad, bloody, merciless, money-grabbing, and predatory as it is – in our 
Title: Mark Twain
Content:  in Providence. In some later writings in the 1890s, he was less optimistic about the goodness of God, observing that "if our Maker is all-powerful for good or evil, He is not in His right mind". At other times, he conjectured sardonically that perhaps God had created the world with all its tortures for some purpose of His own, but was otherwise indifferent to humanity, which was too petty and insignificant to deserve His attention anyway. In 1901, Twain criticized the actions of the missionary Dr. William Scott Ament (1851–1909) because Ament and other missionaries had collected indemnities from Chinese subjects in the 
Title: Letters from the Earth
Content:  Letters from the Earth is a posthumously published work of American author Mark Twain (1835–1910) collated by Bernard DeVoto. It comprises essays written during a difficult time in Twain's life (1904–1909), when he was deeply in debt and had recently lost his wife and one of his daughters. The content concerns morality and religion and strikes a tone that is sarcastic—Twain's own term throughout the book. Initially, Twain's sole surviving child, Clara Clemens, objected to its publication in March 1939, probably because of its controversial and iconoclastic views on religion, claiming it presented a "distorted" view of her father. Henry Nash Smith helped change her position in 1960. Clara explained her change of heart in 1962 saying that "Mark Twain belonged to the world" and that public opinion had become more tolerant. She was also influenced to release the papers by her annoyance with Soviet reports that her father's ideas were being suppressed in the United States. The papers were selected, edited and sequenced for the book in 1939 by Bernard DeVoto.
Title: Theology
Content:  Germany, in which he had said that theology was a "web of contradictions and delusions." The American satirist Mark Twain remarked in his essay "The Lowest Animal", originally written in around 1896, but not published until after Twain's death in 1910, that: "[Man] is the only animal that loves his neighbor as himself and cuts his throat if his theology isn't straight. He has made a graveyard of the globe in trying his honest best to smooth his brother's path to happiness and heaven.… The higher animals have no religion. And we are told that they are going to be left out in the Hereafter. I wonder why? It seems questionable taste."
Title: Pudd'nhead Wilson
Content:  Mark Twain's satire humorously and pointedly lambastes everything from small-town politics and religious beliefs to slavery and racism.
Title: Jesus H. Christ
Content:  The earliest use of the phrase is unknown, but in his autobiography, Mark Twain (1835–1910) observed that it was in general use even in his childhood. Twain refers to an episode from 1847, when he was working as a printer's apprentice; Roger Smith (1994) tells the tale thus: "[Twain] recounts a practical joke a friend played on a revival preacher when Twain was an apprentice in a printing shop that Alexander Campbell, a famous evangelist then visiting Hannibal, hired to print a pamphlet of his sermon. While checking the galleys, Twain's fellow apprentice, Wales McCormick, found he had to make room for some dropped words, 

Question: What is the religion of Mark Twain?
Answer: atheism.
unbelief.