Tom Clancy and Steve Pieczenik wrote the Net Force book series, during the early to mid '90s.

They take place in the year 2010, when "hackers" and cyber terrorists are as common as a car thief. Virtual Reality has come to stay and that is where the cyber crimes are comitted.
Characters include Alex Michaels (director of the Net Force), Jay Gridley (VR scenario creator), Toni Fiorella (Net Force detective, also Michaels' girlfriend) and John Howard (commander of the armed forces of the Net Force).

A good series of books, Clancy's character descriptions are impeccable, you get to know the characters well and they all fit their roles very well. The books don't focus solely on action and computers, there are parts about the characters' relationships and their personal problems aswell.

Some minor details in a couple of the books annoyed this noder quite a lot. I tend to be very picky though, my friend who read the same books didn't even notice the little flaws.