(Most of this information comes from the Publishers Weekly
interview.)
Katherine Neville started researching and writing The Eight in
1977.
She read over 200 (another source says 300) books, cover to cover, for
The Eight. They included The Arabian Nights, Carlyle's
French Revolution, the Koran, the New Testament Apocalyse, and
autobiographies of chess masters.
The original manuscript was about 1200 pages long. (And I'd love to
know what was left out. I also wonder if she'll use any of this material
for future books.)
According to the review in the St. Paul Pioneer Press-Dispatch,
the Game in The Eight is based on a real chess game which was
played in a world championship. Katherine Neville won't tell people which
game it is, but she says she "chose one that had the most moves in it and
tailored the plot to that game. If you understand chess, you can figure
out what game it is, what grand master played it and in what year." (I
don't know a lot about chess, but I'm sure many of you do. If someone
could help me figure out which game this is, I'd really appreciate
it.)