Digital Fortress was my first Dan Brown book; I was told that he has a distinctive writing style and story-telling technique from friends who have read all his books. I wanted to start with one of his books which haven't received such acclaim like the "Da Vinci Code" for example.
The story centers around the NSA and a hyper-super-computer they have built to crack codes. At the start of the book, they realize a new encryption algorithm is up for auction which is claimed to be impossible to decipher (especially for the NSA). But it's not as simple as getting the code and seeing how it works, as the NSA plan to implement a back door for them before the algorithm is released. The story's told through 2 narratives on two main characters.
I must admit, the last 200 pages of the book were hair-raising, and I struggled to put it down. If you like a modern mystery with a believable story, then I can highly recommend this book. Digital Fortress was a slow starter and took me to around page 100 to get deeper into the plot, but for myself, it was totally worth it.