When the NSA's invincible code-breaking machine - encounters a mysterious code it cannot break, the agency calls in its head cryptographer, Susan Fletcher, a brilliant and beautiful mathematician. What she uncovers sends shock waves through the corridors of power. The NSA is being held hostage...not by guns or bombs, but by a code so ingeniously complex that if released it will cripple U.S. intelligence.
"Pure genius...Dan Brown has to be one of the best, smartest, and most accomplished writers in the country"
--Nelson Demille--
"Exceedingly clever. Both fascinating and fun...a considerable achievement"
--Washington Post--
"Brown has assembled a whopper of a plot that will please conspiracy buffs and thriller addicts alike"
--Publishers Weekly--
etc,