On a March day in 1997 when every leaf, blade and twig in Topeka, Kan., was the sere brown of a wasteland, I walked beside a guard through a caged pathway while a tower guard watched us through reflective sunglasses, cradling his shotgun like a baby. I was about to interviewDr. Debora Green, serving a "hard 40" for the arson murder of two of her children, the attempted murder of a third and the near-fatal poisonings of her physician husband.

All my usual gear was forbidden -- no notepad, pen or tape recorder -- and I was uneasy. If Debora talked to me during this four-hour interview, how would I ever remember it all? Could I once again suspend judgment and keep my face clear of my own thoughts? As I walked on, I reminded myself of the credo I've followed for 25 years as a writer of true-crime:

-- We are all human beings, some more afraid than others, with stories to tell, to whom attention must be paid.

-- Never tell a lie to get someone to talk.

-- Never print something when you have promised you will not.

-- Never use information that gullible and naive people blurt out to you, if you know it will hurt them more than it will help your story.

Like hundreds of other people I have interviewed in my career, Debora Green did talk. She was voluble in describing her new captive life and her belief that she had been railroaded into prison, but she was curiously silent on the subject I was most interested in: her own childhood. I've long since learned that things not said are often more telling than words. "Did you have a happy childhood?" I asked.

"It was idyllic," she said.

"Tell me about one of the best times you remember."

She looked at me, puzzled. "Well," she said, finally, "I don't remember anything about my childhood, but I know it must have been idyllic."

And, therein, I had a partial answer; to bury some trauma, the woman had repressed the formative years of her life. I remembered everything we said in the eight hours I spent in the I-MAX unit of the Topeka Correctional Facility that weekend, but not for long. My tape recorder waited in my car so that I could "tip my head" and let all the newly laid tracks in my brain flow out. Had tape recorders been permitted, Debora probably would have let me use one; surprisingly, most subjects have no objections to being put on tape -- a boon to writers who strive for accuracy.

Mine is curious and fascinating work. My job is to present unfathomable tragedies to readers in such a way that they will know and care about victims, understand the psychopathology of murderers, and even sense the emotions of detectives and prosecutors who seek justice. I often receive letters and e-mails with a familiar request: "I want to be a true-crime writer. Please tell me how to find the information and how to get people to talk to me."

Depending on my mood, I either smile or sigh; their request is akin to asking a brain surgeon, "Where do I start cutting, and what do I do after I get inside the patient's head?"

How indeed? I ask myself the same question every time I begin research on a new book. I am always worried that I will never find out enough. And yet invariably I finish with so much information that my editors have to ask me to slice some out, a painful process for any author. I am amazed and humbled by the confidences that people share with me; astounded by the extent to which they are willing to talk about murder, arson, sexual betrayal and other desperate crimes. Their frankness may be a phenomenon not unlike the conversations shared by strangers on a bus or on a plane. Most of us need to have someone really pay attention; so few of us have interested listeners.

Even so, trying to get information from people who have suffered tremendous personal loss or who have every reason not to tell me the truth remains the most daunting aspect of my work. Details of homicide cases can be gleaned from trials, court transcripts and police files, but a book that fails to expose the real people and real feelings behind a crime would be as empty as a milkweed pod when its silk has blown away.

So how do I get people to talk to me? I have an advantage over reporters: I don't have to meet a daily deadline. I can wait months -- years, if need be -- until a case has been adjudicated. I never "ambush" a subject by knocking on his door unannounced and I don't phone if I can first send a letter introducing myself and outlining what I hope to learn.

In most of the cases I've written about, I attended weeks of trial and became a familiar part of that transient world that existed for its duration. When I can't be there, I read the entire court transcript before I approach the principals. Because I believed that my current book -- And Never Let Her Go: Thomas Capano, The Deadly Seducer, about the Delaware murder of Gov. Tom Carper's secretary, Anne Marie Fahey -- had to be as much about the women Capano betrayed as about him, I wanted to talk to Debby MacIntyre, his mistress for 18 years.

Although I wrote to MacIntyre through her attorney, it was the attorney's wife who passed my letter on. She had read an earlier book of mine. In the end, I was the only writer MacIntyre spoke to and I quickly realized she was not the scarlet woman the tabloids made her out to be -- she was unaware that Tom Capano was fatally obsessed with other women; she was yet another of his victims.

The dozens of jail and prison interviews I've done all have a similar script. Indeed, to know a sociopath, you don't ask him; you ask the people whose lives he's touched. "I am innocent," the convicted all tell me. "The prosecutor knows it -- but he won't admit it" and/or "The police are crooked." I have yet to have a convicted killer suddenly blurt a confession to me. I suppose the possibility still remains.

I'm always elated when a defendant takes the witness stand because it obviates the need for an interview. The defendant's version of events may not be the truth, but the way the truth gets twisted is, perhaps, more interesting. Tom Capano testified for days, although his defense attorneys practically flung themselves in his path to keep him from taking the stand and facing the unavoidable and devastating cross-examination by prosecutor Colm Connolly. The charismatic and narcissistic sociopath cannot resist a chance to "explain," invariably convinced that his own genius at rhetoric far outshines any words his lawyers might muster. (Even better, at least for my purposes, is the defendant who insists on serving as his own attorney, a remarkably stupid decision. Capano, an attorney himself, tried to fire his lawyers and handle his case himself, but he was dissuaded.)

Hearing the defendant in the courtroom is the easy way; I dread going into jails and prisons, perhaps due to a low-grade claustrophobia on my part, but I often have no choice. When a series of steel doors clanks shut behind me, I feel it in the beating of my heart. Penal institutions smell of cigarette smoke, Pine-sol and urine, some lockups more pungent than others. When I interview prisoners, I become a sponge. I am there to listen, to assess body language, sometimes to look at the glint in their eyes where the truth shows.

Some of my interviews stand out in memory as if they had taken place only yesterday: talking to serial murderer Ted Bundy, in a tiny space between two electrically controlled doors in a Utah prison; to Diane Downs, chattering at me animatedly on the other side of bullet-proof glass the evening before she gave birth (she had shot her three previous children); to David Arnold Brown, who had insured his wife fraudulently, then brainwashed his teenage daughter into murdering her, and who looked like a groundhog when he flashed me what he imagined to be a charming smile.

Still -- much clearer in my mind -- are the few fortunate people who survived "my" killers, the families of those who died and the witnesses who sometimes risked their lives to testify. Their stories are heartrending and have become part of the fabric of my own life -- friends over the years. Reporters often lapse into easy assessments of murderers: "He was just like the guy next door." Not really; more likely, he was a monster behind the mask. And while the crimes I write about are bizarre and convoluted, the innocent human beings caught up in the tragedies are, in the main, people we would all welcome as neighbors, individuals trapped by an unfortunate synchronicity of time, place and fortune.

In the end, those are the redeeming people: the ones who put humanity in my books.