Phillip Noyce made a deal with the studio that if the production went over budget, he'd pay the difference out of his own pocket, and if they came in under budget, then he would get to keep half.
Phillip Noyce is not a big fan of his work on this film. In the wake of Sieben (1995), every studio wanted a copycat serial killer film on their books. He felt that he was just part of the assembly line by signing on to this film, knowing full well that he would never be able to match David Fincher's achievement.
While Jeremy Iacone stayed faithful to the source material, he condensed the plot "down to three murders" in order to hone in on the dynamic between the lead characters.
In Jeffery Deaver's novel, Amelia Donaghy (Angelina Jolie) was named Amelia Sachs. The filmmakers changed it, because it "sounded a lot like 'sex'".
Phillip Noyce: (at around 1h 30 mins) A man browsing through books in the bookstore that Angelina Jolie enters.