Before the multi-million, runaway bestseller The Da Vinci Code , Dan Brown set his razor-sharp research and storytelling skills on the most powerful intelligence organization on earth--the National Security Agency (NSA)--in this thrilling novel, Digital Fortress . When the National Security Agency’s invincible code-breaking machine encounters a mysterious code it cannot break, the agency calls its head cryptographer, Susan Fletcher, a brilliant, 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 complex that if released would cripple U.S. intelligence. Caught in an accelerating tempest of secrecy and lies, Fletcher battles to save the agency she believes in. Betrayed on all sides, she finds herself fighting not only for her country but for her life. It is a battle for survival—a crucial bid to destroy a creation of inconceivable genius that threatens to obliterate the balance of world power…for all time. This edition of the book is the deluxe, tall rack mass market paperback.