In the popular imagination, chess isn't like a spelling bee or Trivial Pursuit, a competition to see who can hold the most facts in memory and consult them quickly. In chess, as in the arts and sciences, there is plenty of room for beauty, subtlety, and deep originality. Chess requires brilliant thinking, supposedly the one feat that would be--forever--beyond the reach of any computer. But for a decade, human beings have had to live with the fact that one of our species' most celebrated intellectual summits--the title of world chess champion--has to be shared with a machine, Deep Blue, which beat Garry Kasparov in a highly publicized match in 1997. How could this be? What lessons could be gleaned from this shocking upset? Did we learn that machines could actually think as well as the smartest of us, or had chess been exposed as not such a deep game after all?

The following years saw two other human-machine chess matches that stand out: a hard-fought draw between Vladimir Kramnik and Deep Fritz in Bahrain in 2002 and a draw between Kasparov and Deep Junior in New York in 2003, in a series of games that the New York City Sports Commission called "the first World Chess Championship sanctioned by both the Fédération Internationale des Échecs (FIDE), the international governing body of chess, and the International Computer Game Association (ICGA)."