LOS ANGELES -- It's telling that the title of Marcia Clark's murder-mystery debut is smaller than her name on the novel's cover.

Clark is best known as the lead prosecutor in the media circus known as the O.J. Simpson murder trial. She's less recognized as an author, even though her 1998 book about the case, "Without a Doubt," spent nine weeks on the New York Times best-seller list.

Co-writing a book about one of the most notorious trials of the past century "didn't have much leeway. I had a story that had to be told, and the facts were there," Clark said.

Penning "Guilt by Association," out April 20, was a lot easier and more "joyful" for the former Los Angeles deputy district attorney, who resigned in 1997 and now does court-appointed appellate work and appears as a special correspondent for "Entertainment Tonight."

She's been working on her debut novel since 2006.

'Beach read'

Most best-selling authors would agree: One chart-topping book is no guarantee that the follow-up will do as well, especially when the genre is as radically different as it is with "Guilt by Association." The story follows fictional L.A. Deputy D.A. Rachel Knight as she attempts to solve the murder of a colleague and the rape of a Pacific Palisades high school student. It's "a beach read," according to Clark.

Knight is a sassy, single, middle-age brunette -- an underpaid workaholic who believes in justice but disdains authority. Jaded and occasionally self-indulgent, she's more than a little like Clark.

"There's a lot of me in there," admitted Clark, laughing between sips of iced tea at the Millennium Biltmore Hotel, where her literary alter ego resides in the novel. "A lot of the bad stuff."

Now 57, Clark looks and acts far younger than her years. Gone is the wavy hairdo that was analyzed almost daily during the nine-month Simpson trial. In its place is a sleek brown bob. Instead of the stress and chain smoking are an easy smile and warm demeanor that belie the bulldog nature she demonstrated in her attempts to convict Simpson in the murders of his ex-wife, Nicole Brown Simpson, and her friend, Ronald Goldman, in 1994.

"Rachel's attitude is probably me. She's compulsive, obsessive, dedicated and driven. I think I'm that kind of hockey puck," Clark said, bursting into a laugh.

Clark never intended to incorporate so much of herself into her lead character, but after writing draft after draft of various books and showing them to friends and agents, she was confronted with the criticism that Rachel Knight, who works the same job as Clark did in the L.A. D.A.'s special trials unit, was an unreal "cream puff."

Shaping the novel

Showing the same dedication to writing as she demonstrated with trial work, Clark spent years experimenting.

Decades of reading murder-mysteries was little preparation for the trial and error of fiction writing as she switched between the first- and third-person points of view and worked with various plots, only to finally find the voice and story line for "Guilt by Association" -- the first of a two-book deal with Little, Brown's Mulholland Books imprint. The follow-up, tentatively titled "Guilt by Degrees," will be out next spring.

"The writing process probably could have been easier than I made it," she said of writing the novel. "But you know, that's not my way.

"I've heard many authors say that they put in five to six hours a day and then knock off for the day. That didn't work for me. I needed to write nonstop until I got to the end," Clark said. "So I plunked myself down in front of the computer every single day and stayed there for as long as possible, sometimes 10 hours at a stretch, till I was cross-eyed and my shoulders were permanently wedged up against my ears.

"It's kind of a kamikaze approach to writing, but it helped to keep me inside the story and the characters."

'Umbrella truths'

The specific scenarios and characters in the book are entirely fictional, Clark says. Still, her personal legal experience lends the plots and personalities legitimacy and provides intriguing insights into the inner workings of the judicial system and the importance of personal relationships in getting things done.

There are unintentional echoes of the Simpson trial in "Guilt by Association." The murder in the book has sexual undertones, and there's an air of racism to the rape, which involves members of Latino and white supremacist gangs.

"There are certain umbrella truths that are ever present in trials not just in L.A. but across the country," Clark said. "Does race factor in? Sure. Gender bias? Absolutely. In my opinion, gender bias is a bigger problem than race."

Clark speaks from experience. She was the first woman to serve in the special trials unit in L.A.'s district attorney's office in the '90s. Contrary to public perception, Clark said she never experienced gender bias from Simpson attorney Johnnie Cochran or Judge Lance Ito during the trial.

Even 16 years after O.J. Simpson was acquitted, Clark said she still thinks about the case every day.

"I think about a lot of my old cases. Not just that one," Clark said. "There's so much sadness. Handling those kinds of cases where loved ones were murdered and you're dealing with the victims, their lives are forever changed no matter what you do. There's no amount of justice that can take away the hurt or pain they go through. You live it with them and carry some part of it with you. You never get away from that."