On the Decay of the Art of Lying, published in The Stolen White Elephant: Etc, Pages 220-221 http://books.google.com/books?id=rTv19WvJto4C&q=%22The+highest%22+%22perfection+of+politeness+is+only+a+beautiful+edifice+built+from+the+base+to+the+dome+of+graceful+and+gilded+forms+of+charitable+and+unselfish+lying%22&pg=PA221#v=onepage (1882)

“Pilgrim's Progress, about a man that left his family, it didn't say why. I read considerable in it now and then. The statements was interesting, but tough.”

Mark Twain book Adventures of Huckleberry Finn

Source: Adventures of Huckleberry Finn (1885), Ch. 17

“Principles have no real force except when one is well-fed.”

Mark Twain

Extracts From Adam's Diary (1906)

“A Jewish beggar is not impossible, perhaps; such a thing may exist, but there are few men that can say they have seen that spectacle.”

Mark Twain book Concerning the Jews

Concerning the Jews (Harper's Magazine, Sept. 1899)

“I have seen it stated that no expert is quick enough to run over a dog; that a dog is always able to skip out of his way. I think that that may be true; but I think that the reason he couldn't run over the dog was because he was trying to. I did not try to run over any dog. But I ran over every dog that came along.”

Mark Twain

"Taming the Bicycle" (1917)

“Laws are sand, customs are rock. Laws can be evaded and punishment escaped, but an openly transgressed custom brings sure punishment.”

Mark Twain

The Gorky Incident (1906)

“James Ross Clemens, a cousin of mine, was seriously ill two or three weeks ago in London, but is well now. The report of my illness grew out of his illness; the report of my death was an exaggeration.”

Mark Twain

From a note Twain wrote in London on May 31, 1897 to reporter Frank Marshall White: Shelley Fisher Fishkin, Lighting Out For the Territory : Reflections on Mark Twain and American Culture (Oxford University Press, 1996), p. 134 http://books.google.com/books?id=ms3tce7BgJsC&lpg=PA134&vq=%22the%20report%20of%20my%20death%20was%20an%20exaggeration%22&pg=PA134. (The original note is the Papers of Mark Twain, Accession #6314, etc., Clifton Waller Barrett Library, Special Collections, University of Virginia Library, Charlottesville, Va. http://ead.lib.virginia.edu/vivaxtf/view?docId=uva-sc/viu00005.xml, in Box 1.) White subsequently reported this in "Mark Twain Amused," New York Journal, 2 June 1897. White also recounts the incident in "Mark Twain as a Newspaper Reporter," The Outlook, Vol. 96, 24 December 1910 "Chapters from My Autobiography", The North American Review, 21 September 1906, p. 160. Mark Twain Misquote: The reports of my death are greatly exaggerated. This paraphrase or misquote may be more popular than the original. Variant: I said - 'Say the report is greatly exaggerated'.

“He [George Washington Cable] has taught me to abhor and detest the Sabbath day and hunt up new and troublesome ways to dishonor it.”

Mark Twain

Letter to William Dean Howells, 27 February 1885, in Albert Bigelow Paine, Mark Twain's letters: Arranged with Comment (1917), Vol. 2, p. 450 http://books.google.com/books?id=4KZhv9y8sMIC&pg=PA450&lpg=PA450

“It is wonderful, the power of a faith like that, that can make multitudes upon multitudes of the old and weak and the young and frail enter without hesitation or complaint upon such incredible journeys and endure the resultant miseries without repining. It is done in love, or it is done in fear; I do not know which it is. No matter what the impulse is, the act born of it is beyond imagination marvelous to our kind of people, the cold whites.”

Mark Twain book Following the Equator

referencing the Kumbh Mela, Ch. XLIX
Following the Equator (1897)

“Geological time is not money. A pity too; for it would have abolished poverty from the earth. Let us adopt geological time, then time being money, — there will be no more poverty. We are all missionaries (propagandists of our views). Each of us disapproves of the other missionaries; in fact detests them, as a rule. I am one of the herd myself. It is noticeable that the professional always uses the one license: "Go ye into all the world," and ignores the Golden Rule which would restrain him from entering China and one or two other countries where he is not wanted and is not welcome.”

Mark Twain

Source: Mark Twain's Notebook (1935), p. 393

“Describing her first day back in grade school after a long absence, a teacher said, "It was like trying to hold 35 corks under water at the same time."”

Mark Twain

Incorrectly attributed to Twain, this is actually a quotation from an article in The Pocono Record (18 February 1971, page 4 http://www.newspapers.com/newspage/40447792/) Misattributed

“Weather is a literary specialty, and no untrained hand can turn out a good article on it.”

Mark Twain book The American Claimant

The American Claimant, foreword (1892)

“That is a simple rule, and easy to remember. When I, a thoughtful and unblessed Presbyterian, examine the Koran, I know that beyond any question every Mohammedan is insane; not in all things, but in religious matters. When a thoughtful and unblessed Mohammedan examines the Westminster Catechism, he knows that beyond any question I am spiritually insane.”

Mark Twain

Twain, Mark - Christian Science: Book I. Chapter V http://www.classicreader.com/book/1286/6/

“Truth is the most valuable thing we have. Let us economize it.”

Mark Twain book Following the Equator

Pudd'nhead Wilson's New Calendar, Ch. VII
Following the Equator (1897)