Writing about these women has inspired her to speak out against domestic violence and to advocate support groups for its victims.
But in her new book, "Heart Full of Lies: A True Story of Desire and Death," Rule goes in a totally different direction, delving into the mind of a charismatic woman who seduced, manipulated and callously betrayed the men who adored her.
Rule tells The Early Show co-anchor Hannah Storm, "I'm always looking for cases that you cannot predict the end. And on occasion, I've had men call me and say, 'Why are you always defending women? Sometimes it works the other way.'"
So when she got many e-mails asking her to write about pilot Chris Northon's death, she decided to look into it. "And I didn't know when I went in, what the truth was," she says.
"Heart Full of Lies" is the story of what she discovered. In October 2000, in the soaring mountains of Oregon, 38-year-old femme fatale Liysa Northon murdered her husband. But before taking the life of Chris Northon, Liysa took great pains to frame him as a wife beater.
Rule says, "I had first to prove to myself that Chris was the victim and not the wife beater she had portrayed him to be. And once I was convinced of that and looked into her background, I saw a pattern."
Liysa Northon, who is in jail for the murder of her husband, didn't have the typical characteristics of a murderer. She was a homecoming queen - attractive and bright - and had these two beautiful children. And yet, she shot her husband in cold blood as he was sleeping in a sleeping bag.
Rule notes, "I think the basic personality is already there. And what I'm looking for are people who seem to have everything. And, yet, inside, behind the mask, there's somebody else entirely different."
She said after looking through the pattern of Liysa's life, rule discovered the woman wanted things and property and fame and money.
"What I try to do is show the why of murder, not the grizzly how of murder any more than I have to, but who are these people and how did they develop? And sometimes I can really explain it and sometimes I can't. She's a little more difficult."
Click here to read an excerpt from "Heart Full of Lies."