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)
Mark Twain Quotes
advice to his brother Orion, p. 8.
Autobiography of Mark Twain, Volume 1 (2010)
Source: The Innocents Abroad (1869), Ch. 19.
“A baby is an inestimable blessing and bother.”
Letter to Annie Moffett Webster (1 September 1876)
Source: The Adventures of Tom Sawyer (1876), Ch. 13
Source: A Connecticut Yankee in King Arthur's Court (1889), Ch. 13.
“Soap and education are not as sudden as a massacre, but they are more deadly in the long run.”
"The Facts Concerning the Recent Resignation", described by the author as written about 1867, first published in Mark Twain's Sketches, New and Old http://books.google.com/books?id=5LcIAAAAQAAJ (1875)
Source: Mark Twain's Notebook (1935), p. 394.
“An experienced, industrious, ambitious, and often quite picturesque liar.”
"The Private History of a Campaign That Failed", The Century, Vol. 31, No. 2, December 1885 http://books.google.com/books?id=-1UiAQAAIAAJ&pg=PA193. Anthologized in The American Claimant, and Other Stories and Sketches http://books.google.com/books?id=1T00Sc_cVYIC (1898)
Bible Teaching and Religious Practice http://books.google.com/books?id=sujuHO_fvJgC&pg=PA568&dq=twain+%22Bible+Teaching+and+Religious+Practice%22&cd=1#v=onepage&q=twain%20%22Bible%20Teaching%20and%20Religious%20Practice%22&f=false.
"Bible Teaching and Religious Practice" (1923)
Source: Adventures of Huckleberry Finn (1885), Ch. 12
Source: Mark Twain's Autobiography (1924), p. 98
Statement (1906) in Mark Twain in Eruption: Hitherto Unpublished Pages About Men and Events (1940) edited by Bernard DeVoto
“When in doubt, tell the truth.”
Pudd'nhead Wilson's New Calendar, Ch. II
Not in the text, but added by many sources is the sentence: "It will confound your enemies and astound your friends." Compare this line to the advice attributed to Henry Wotton (1568 - 1639) to a young diplomat "to tell the truth, and so puzzle and confound his enemies." E.g., Vol 24, Encyclopedia Britannica of Arts, Sciences, and General Literature, page 721 https://books.google.com/books?id=_GlJAAAAYAAJ&pg=PA721&lpg=PA721&dq=truth+wotton+confound+advice&source=bl&ots=-cGk3UDLLj&sig=ltOR1xtI9WFic1JWKiFmIZ8Yce0&hl=en&sa=X&ved=0ahUKEwjVkZCsj-jRAhXCyFQKHTmsCkAQ6AEIODAG#v=onepage&q=truth%20wotton%20confound%20advice&f=false (9th Ed. 1894)
Following the Equator (1897)
Source: Autobiography of Mark Twain, Volume 1 (2010), p. 121
Epitaph for his daughter, Olivia Susan Clemens (1896), this is actually a slight adaptation of the poem "Annette" by Robert Richardson; more details are available at "The Poem on Susy Clemens' Headstone" http://www.twainquotes.com/headstone.html
Misattributed
“Everybody talks about the weather, but nobody does anything about it.”
Notes on sourcing http://www.bartleby.com/73/1982.html
Twain did say:
: "There is a sumptuous variety about the New England weather that compels the stranger's admiration — and regret. The weather is always doing something there … In the spring I have counted one hundred and thirty-six different kinds of weather inside of four and twenty hours. ...
Yes, one of the brightest gems in the New England weather is the dazzling uncertainty of it."
:* Speech at the dinner of New England Society in New York City (22 December 1876)
Misattributed
Source: Autobiography of Mark Twain, Vol. 2 (2013), p. 304
"A New Crime" (1870)
Source: The Innocents Abroad (1869), Ch. 42
Source: Autobiography of Mark Twain, Volume 1 (2010), pp. 21–22
Is Shakespeare Dead? (1909), §11, as reprinted in Essays and Sketches of Mark Twain (1995), ed. Stuart Miller, ISBN 1566198798
Concerning the Jews (Harper's Magazine, Sept. 1899)
“I don't give a damn for a man who can only spell a word one way.”
Unsourced in POP!: Create the Perfect Pitch, Title, and Tagline for Anything (2006) by Sam Horn.
Disputed
Source: The Adventures of Tom Sawyer (1876), Ch. 5
Source: Autobiography of Mark Twain, Vol. 3 (2015), p. 219, of his "angel-fishes"—girls between the ages of ten and sixteen whom he befriended after the death of his wife
Source: Autobiography of Mark Twain, Vol. 2 (2013), p. 281
“Prosperity is the best protector of principle.”
Pudd'nhead Wilson's New Calendar, Ch. II ; as cited in Mark Twain at your Fingertips https://en.wikiquote.org/wiki/Special:BookSources/0486473198: A Book of Quotations, ed. Caroline Thomas Hornsberger, Courier Corp. (2009), p. 385
Following the Equator (1897)
"The Man That Corrupted Hadleyburg", ch. III, in The Man That Corrupted Hadleyburg and Other Stories and Essays (1900)
"The Man That Corrupted Hadleyburg", ch. III, in The Man That Corrupted Hadleyburg and Other Stories and Essays (1900)
“Man will do many things to get himself loved; he will do all things to get himself envied.”
Pudd'nhead Wilson's New Calendar, Ch. XXI
Following the Equator (1897)
Variant: Man will do many things to get himself loved, he will do all things to get himself envied.
Source: The Adventures of Tom Sawyer (1876), Ch. 2
“How easy it is to make people believe a lie, and [how] hard it is to undo that work again!”
Misquote: It's easier to fool people than to convince them that they have been fooled.
Source: Autobiography of Mark Twain, Vol. 2 (2013), p. 302
Source: Autobiography of Mark Twain, Volume 1 (2010), p. 161
Source: Mark Twain's Notebook (1935), p. 343
“To create man was a fine and original idea; but to add the sheep was a tautology.”
St. Louis Post-Dispatch (30 May 1902); also in Mark Twain : A Life, p. 611
"My First Lie, and How I Got Out of It" http://www.mtwain.com/My_First_Lie,_And_How_I_Got_Out_Of_It/0.html, in The Man That Corrupted Hadleyburg and Other Stories and Essays (1900)
Source: Autobiography of Mark Twain, Volume 1 (2010), p. 16
"Man's Place in the Animal World" (1869)
Source: Autobiography of Mark Twain, Volume 1 (2010), p. 441
Czar Nicholas II
1905
Collected Tales, Sketches, Speeches, & Essays, 1891-1910 (1992) ed. Louis J. Budd
Source: Adventures of Huckleberry Finn (1885), Ch. 18
"License of the Press", an address before the Monday Evening Club, Hartford (1873)