The Innocents Abroad, 1869 (travel)
Roughing It, 1872 (travel)
The Adventures of Tom Sawyer, 1876 (novel)
The Prince and the Pauper, 1881 (novel)
Life on the Mississippi, 1883 (memoir)
Adventures of Huckleberry Finn, 1885 (novel)
A Connecticut Yankee in King Arthur's Court, 1889 (novel)
Pudd'nhead Wilson, 1894 (novel)
The Autobiography of Mark Twain, 1924 (memoir)
The Oxford Mark Twain, 1997 (29-volume collection of works published in Twain's lifetime)
Kaplan, Justin. Mr. Clemens and Mark Twain: A Biography. New York: Simon & Schuster, 1966.
Powers, Ron. Mark Twain: A Life. New York: Free Press, 2005.
Ward, Geoffrey C., Dayton Duncan, and Ken Burns. Mark Twain: An Illustrated Biography. New York: Alfred A. Knopf, 2001.
Google Books has the entire text of The Adventures of Tom Sawyer available for download in PDF format. The text is also searchable by word or phrase.
Mark Twain: A Film Directed by Ken Burns. The website that accompanies the PBS film Mark Twain, a documentary directed by Ken Burns, includes classroom activities, selected writings, a chronology of Twain's life, and links to related websites.
The Mark Twain House & Museum. The mission of The Mark Twain House & Museum is to foster an appreciation of the legacy of Mark Twain as one of our nation's defining cultural figures and to demonstrate the continuing relevance of his work, life, and times.
The Mark Twain Project. A collaboration between the Mark Twain Papers and Project of The Bancroft Library, the California Digital Library, and the University of California Press, this website contains reliable texts, accurate and exhaustive notes, and the most recently discovered letters and documents. Its ultimate purpose is to produce fully annotated, digital editions of everything Mark Twain wrote.