Mark Twain had some 50 pieces of fiction and non-fiction published prior to his death in 1910 at the age of 74. (Associated Press)

An anthology of unpublished stories and essays by Mark Twain will be coming out in April, 99 years after his death.

Who is Mark Twain? is a compilation of 24 pieces — published by HarperStudio — put together by Robert Hirst, general editor of the Mark Twain Project at the University of California.

Twain left behind one of the largest collections of personal papers by any 19th century American author.

"The pieces themselves are wonderfully, hilariously contemporary, and deserve as wide an audience as possible," publisher Bob Miller told the Guardian newspaper.

The title is a sly reference to Twain's essay, Frank Fuller and My First New York Lecture — which is included in the book.

In that piece, Twain describes how he placed advertisements all over New York to promote a lecture he was giving out of fear no one would come. He then overheard two men discussing one of the ads. One of the men asked, "Who is Mark Twain?" to which the other replied: "God knows — I don't."

The anthology also contains the unpublished short story The Undertaker's Tale, described as a "tongue-in-cheek piece" about the funeral industry.

While another essay examines the plot stylings of Jane Austen, who Twain notes, always seems to "make the reader detest her people up to the middle of the book and like them in the rest of the chapters."

Twain, who was born Samuel Clemens in Florida, Mo., is often called the "father of American literature."

Known for his two classic books — Adventures of Huckleberry Finn and The Adventures of Tom Sawyer — he was also a widely-published humourist and travel writer.

After having some 50 works of fiction and non-fiction published, he died at the age of 74 on April 21, 1910.