Mark Twain's writings typically could be described as what genre?

The more appropriate question might be, "What genres did
Mark Twain NOT write in?" because a look at his life's work indicates a wide variety of
types of writing: anthologies, autobiographical writing, essays, plays, short stories,
travelogues, and of course the novels for which he is probably most famous, including
but certainly not limited to The Adventures of Huckleberry Finn and
Tom Sawyer.  The pseudonym "Mark Twain" is taken from Clemens's
time as a riverboat pilot on the Mississippi shortly before the American Civil War
began.  From 1857 to 1860, Clemens/Twain was an apprentice, then a practicing riverboat
pilot, and the practical knowledge of the river makes its way into many of his writings,
most notably, Life on the Mississippi, which, although generally
categorized as a travel book, also contained anecdotes of an historical/geographical
nature, as well as references to folklore and local color.