Question: Who is best known for his work in alternate history, John Irving or Harry Turtledove?

Context paragraphs:
The Two Georges: The Two Georges is an alternate history novel co-written by science fiction author Harry Turtledove and Oscar-winning actor Richard Dreyfuss.  It was originally published in 1995 by Hodder & Stoughton in the United Kingdom, and in 1996 by Tor Books in the United States, and was nominated for the 1995 Sidewise Award for Alternate History.

Harry Turtledove: Harry Norman Turtledove (born June 14, 1949) is an American novelist, best known for his work in the genres of alternate history, historical fiction, fantasy, and science fiction.

Worldwar series: The Worldwar series is the fan name given to a series of alternate history science fiction novels by Harry Turtledove.  Its premise is an alien invasion of Earth during World War II, and includes Turtledove's "Worldwar" tetralogy; as well as the "Colonization" trilogy; and the novel Homeward Bound.  The series' time-span ranges from 1942–2031.  The early series was nominated for a Sidewise Award for Alternate History in 1996.

Lest Darkness Fall: Lest Darkness Fall is an alternate history science fiction novel written in 1939 by author L. Sprague de Camp.  The book is often considered one of the best examples of the alternate history genre; it is certainly one of the earliest and most influential.  Prominent alternate history author Harry Turtledove has said it sparked his interest in the genre as well as his desire to study Byzantine history.

The Last Article: "The Last Article" (1988), is an alternate history short story by Harry Turtledove.  The story describes a Nazi invasion of India and the reaction of the Germans to the nonviolent resistance and pacifism of Mohandas Gandhi and his followers.  This story was later reprinted in Turtledove's short-story collection "Kaleidoscope" in 1990, and the variety showcase "The Best Military Science Fiction of the Twentieth Century" in 2001.

Give Me Back My Legions!: Give Me Back My Legions!  is a 2009 historical novel by Harry Turtledove.  While Turtledove is mainly known for alternate history novels, this novel is a historical novel, in which the real-life events leading up to the Battle of the Teutoburg Forest, as well as the battle itself, are re-created.

The Great War: American Front: The Great War: American Front is the first alternate history novel in the Great War trilogy by Harry Turtledove.  It is the second part of Turtledove's Southern Victory series of novels.  It takes the Southern Victory Series from 1914 to 1915.

American Empire: The Center Cannot Hold: American Empire: The Center Cannot Hold is the second book in the "American Empire" alternate history series by Harry Turtledove.  It takes place during the period of the Roaring Twenties and the Great Depression (specifically from 1924 to March 4, 1934).  During this era in Turtledove's Southern Victory world, the Confederate States of America, stretching from Sonora to Virginia, is led by Whigs (with the fascist Freedom Party gaining more and more power) while the United States of America (which has been occupying Canada, Newfoundland, the Bahamas, Bermuda, and the Sandwich Islands) is controlled by Socialists.

How Few Remain: How Few Remain is a 1997 alternate history novel by Harry Turtledove.  It is the first part of the Southern Victory saga, which depicts a world in which the Confederacy won the American Civil War.  It is similar to his earlier novel "The Guns of the South", but unlike the latter, it is a purely historical novel with no fantastical or science fiction elements.The book received the Sidewise Award for Alternate History in 1997, and was also nominated for the Nebula Award for Best Novel in 1998.  It covers the Southern Victory Series Earth period of history from 1862 and from 1881 to 1882.

John Irving: John Winslow Irving (born John Wallace Blunt, Jr. on March 2, 1942) is an American novelist and screenwriter.

Supporting paragraphs: John Irving Harry Turtledove
Answer: Harry Norman Turtledove