Developed over four years at an estimated cost of more than $30 million, IBM's "Jeopardy"-playing computer, Watson, will face the quiz show's grand masters, Ken Jennings and Brad Rutter, in two games to be aired Feb. 14, 15 and 16. As Stephen Baker relates in the following excerpt from his new book, "Final Jeopardy: Man vs. Machine and the Quest to Know Everything," doubts remain about how well Watson can process the endless subtleties of human language.

Watson paused. The closest thing it had to a face, a glowing orb on a flat-panel screen, turned from forest green to a dark shade of blue. Filaments of yellow and red streamed steadily across it, like the paths of jets circumnavigating the globe. This pattern represented a state of quiet anticipation as the supercomputer awaited the next clue.

As Todd Crain, an actor and the host of these test games, started to read the next clue, the filaments on Watson's display began to jag and tremble. Watson was thinking—or coming as close to it as a computer could. The $1,600 clue, in a category called "The eyes have it," read: "This facial wear made Israel's Moshe Dayan instantly recognizable world-wide."

The three players—two human and one electronic—could read the words as soon as they appeared on the big "Jeopardy" board. But they had to wait for Mr. Crain to read the entire clue before buzzing. That was the rule. At the moment the host pronounced the last word, a light would signal that contestants could buzz. The first to hit the button could win $1,600 with the right answer—or lose the same amount with a wrong one. (In these test matches, they were playing with funny money.)