When the National Security Agency's "invincible" code-breaking machine encounters a mysterious code it cannot break, the agency calls in its head cryptographer, Susan Fletcher, a brilliant, beautiful mathematician. What she uncovers send shock waved 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 it would cripple US 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, and in the end, for the man she loves...

Well that's what the blurb on the cover says. Digital Fortress is more of the same from Da Vinci Code author Dan Brown - talk of codes and crytography with fast-paced action. Unfortunately the characters here are not as engaging as Da Vinci Code, but the book is enjoyable enough, easy reading with plenty of mentions of the main character's designer shoes to prove that not only is she a genius mathematician, but a fashionista to boot.