Horrors told. (Soundbite).

The cruel system of Soviet work camps known as the gulag terrorized some 18 million prisoners--and yet its history has been relatively overlooked in the catalog of 20th-century horrors. That's why Washington Post editorialist Anne Applebaum devoted the last six years to writing the fascinating, horrifying Gulag: A History (Doubleday).

Applebaum spent much of the late 1980s and early '90s in Eastern Europe, covering the region for The Economist and other publications. "I met lots of [gulag] survivors," she says. "Coming back to the West, I realized nobody here knew anything about it." After failing to find someone who would write a history, she decided to do it herself, making broad use of extensive archives released by Moscow after the fall of the Soviet Union.

Assistant Editor Sara Rimensnyder spoke to Applebaum by phone in May.

Q: What was the most horrifying aspect of the gulag?

A: Everybody will have some anecdote or incident that resonates with them; it's very personal. In my case, since I wrote the book at the same time that I had two children, the stories of children born in the camp or taken away from their parents were the worst.

Q: What was the most unexpected thing you discovered?

A: The degree to which it was perfectly well known at the highest echelons of the Soviet bureau cracy how horrible conditions were in great detail. And yet nothing was done.

Q: What is the most important lesson to be learned from a study of the gulag?

A: When people write books about terrible tragedies of the past, they often say they're doing it so it will never happen again. While reading the history of the gulag and the way the Soviets spread it to other countries, I thought, "I'm not writing this so it won't happen again; I'm writing because it will." The alacrity with which other countries took up the idea is remarkable.

The lesson is that this kind of system has been built many times and will be built many more times. lam the last person who would claim the gulag was unique. The mistreatment of other human beings, and especially one's enemies, goes on and will continue to go on. We need to try much harder to understand what it is that persuades people to do it.

Q: Is bureaucracy to blame?

A: It's not just bureaucracy; it's ideology. A lot of people believed in what they were doing. They believed these were enemies of the people and could be treated like building materials, like units of labor. And could be worked to death if necessary.