"The Celebrated Jumping Frog of Calaveras County" ( 1867 ).
The Innocents Abroad ( 1869 ).
Roughing It ( 1872 ).
The Gilded Age ( 1874 ). A collaboration with Charles Dudley Warner.
The Adventures of Tom Sawyer ( 1876 ).
A Tramp Abroad ( 1880 ).
The Prince and the Pauper ( 1882 ).
Life on the Mississippi ( 1883 ).
Adventures of Huckleberry Finn ( 1885 ). Norton Critical Edition, edited by Scully Bradley and others.
A Connecticutt Yankee in King Arthur's Court ( 1889 ). On Line. Norton Critical Edition, edited by Allison R. Ensor.
The Tragedy of Pudd'nhead Wilson ( 1894 ). Norton Critical Edition, edited by Sidney E. Berger.
Personal Recollections of Joan of Arc ( 1896 ).
Following the Equator ( 1897 ).
The Man that Corrupted Hadleyburg ( 1900 ).
The Mysterious Stranger ( 1916 ).
Ever the Twain Shall Meet, Searching Mark Twain. Good sites for locating specific works by Twain.

About Twain

Delancey Ferguson, Mark Twain: Man and Legend. BobbsMerrill, 1943.
E. Hudson Long, J.R. LeMaster, The New Mark Twain Handbook. Garland Pub., 1985.
J.R. LeMaster, James D. Wilson, eds., The Mark Twain Encyclopedia. Garland Pub., 1993.
R. Kent Rasmussen, Mark Twain A to Z: The Essential Reference to His Life and Writings. Oxford, 1995.
Forrest G. Robinson, ed., The Cambridge Companion to Mark Twain. Cambridge, 1995.
Peter Salwen's Mark Twain Page.
Mark Twain in Cyberspace.
Mark Twain in His Times by Stephen Railton.
Mark Twain by Donna Campbell.
Mark Twain from PBS.