"What do you imagine child pornography to be?"

So asked Det. Sgt. Paul Gillespie of a group of Microsoft executives back in 2003, as he sought their help in gaining a hold on the crime on the Internet.

Most of us would not want to answer that question; most of us have never wanted to picture child porn.

 But if we had to answer, we would likely imagine creepy guys hunched over computers in their basements, staring at pictures of undressed girls.

As Julian Sher found while researching his new book "One Child at a Time: The Global Fight to Rescue Children from Online Predators," today's child porn is so much more than that. Sher calls the trade in child porn the new face of crime in the 21st century.

"It's a crime that lives and breathes on the Internet, in the wires in your computer," Sher told Canada AM.

"It's an illegal product that's actually sent through the Internet. I mean, you can't send drugs through the Internet. You can't send guns through the Internet but you can send these horrific pictures of these children."

The author found child porn's most frightening and sometimes most unremorseful perpetrators are often well-to-do, educated, sometimes married men.

"What was so fascinating was that these criminals are us," Sher told CTV.ca in a phone interview from his Montreal home.

"I've done stories on bikers and other type of criminals, but what makes these criminals so scary is that they are among us."

And the pictures these criminals are trading are no longer just of pre-pubescent girls. A disturbingly sizable portion now involves toddlers, even babies.

"About 19 per cent of these victims are under three years old. So think about that. These are infants being abused and tortured. It has nothing to do with sex or eroticism, by any stretch. It's not even pornography; it's child exploitation."

Many of those trading these images are highly tech-savvy, trading thousands of picture files across encrypted connections, covering their tracks as they go and staying one step ahead of authorities.

That was precisely the problem that Gillespie ran into as head of the Toronto child exploitation unit. No matter how much he learned about how those who trade in child porn use technology to hide their crime, he couldn't keep up. He was, after all, a cop, not a computer programmer and he was growing frustrated with how little headway he was making.

So in a moment of frustration, he decided to write an angry letter to the man in charge of the biggest computer company in the world. "You created this mess," his email to Bill Gates essentially read, "You find a way to clean it up."

Gillespie never expected a response, but in fact, Gates did read that email, and did decide to take action. He asked to meet with Gillespie and not long after, the pair helped create CETS, the Child Exploitation Tracking System, a database system that would allow multiple law enforcement agencies to streamline their efforts by cross-referencing data about known child pornographers.

Sher was able to meet Gillespie just as he was getting CETS off the ground. Gillespie agreed to let the award-winning investigative journalist into his world and learn about what would soon became an international collaborative effort to stamp out child exploitation.

"I had the real privilege of working with the Toronto squad and the UK squad, CEOP (Child Exploitation and Online Protection Centre). I followed undercover FBI agents as they tracked predators," Sher says.

The author shows how police are finally making headway at stamping out these crimes by working together to follow the money trails and seize the offshore bank accounts of porn merchants.

They are also turning the technology of the Internet against the perpetrators to piece together clues within the disturbing images they seize to identify and rescue the victims.

The book also includes a full list of resources for concerned parents so they can learn how to prevent their own children from being lured by predators.

Sher's book is fascinating as a guide to what law enforcement agencies are doing to nab online predators. But it is also an exploration of the crime of child pornography and of pedophiles themselves.

The author examines what little real research exists in this still uncharted area of psychology and seeks to understand the mind of the child pornographer "to explore who they are and how they got the way they are."

"One of the most fascinating discussions I had was with a convicted pedophile," Sher says, referring to a relationship he struck with a convicted sex abuser from Edmonton whom he calls "Mark."

Mark agreed to talk to Sher about his pedophilia. He revealed that he knew he was sexually attracted to children from a very early age, from about puberty. Mark began exploring his interest by hanging around swimming pools as a teenager before being arrested at 18 for assaulting his four-year-old niece.

"Mark was very forthcoming," Sher remembers. "He said, 'I knew what I felt was wrong and I tried to stay straight.'"

Mark did stay straight until the day he discovered the Internet. That's when everything changed for him. While he concedes the Internet didn't make him later commit the crimes he did, it exposed him to an entire community of people who had fantasies just like his.

Mark is currently serving a 14-year sentence for abusing two of his step-children and two of their friends. While Mark feels shame, Sher's book introduces us to several other child pornographers who truly believe that they are doing nothing wrong, that they have a right to explore this side of their sexuality and that it is society that has it all wrong.

Sher describes the terrible crimes of a man he calls Burt Thomas Stevenson, who not only repeatedly assaulted his own daughter and sold pictures of that abuse on the Internet, he also abused his four-month-old niece and instructed a fellow pedophile about how to think of his victims as "pieces of meat."

It's harrowing stuff and stuff that Sher admits he knew little about before writing this book.

In the book's acknowledgements, Sher notes that he has written five books on topics such as organized crime, the Hells Angels and the Ku Klux Klan.

"This was by far the most difficult subject I have ever had to confront."