"Solitary confinement is terrible. I don't wish it for anybody," said Esfandiari.
While on a visit to Tehran to see her aging mother, the Iranian-American scholar was sent to Iran's notorious Evin Prison and held there for almost four months. Her crime? Iranian authorities believed she was part of a plan by the Bush administration to oust Iran's rulers.
"Their perception was that the United States is no longer interested in a military intervention in Iran. But it still has a plan for regime change and the way they intend to go about this regime change is through foundations and think tanks," said Esfandiari.
Esfandiari works at the Woodrow Wilson center, a think tank in Washington, organizing conferences on the Middle East. The center is headed by former congressman Lee Hamilton, who says Esfandiari is not a democracy activist.
"(She has) absolutely no connection," said Hamilton. "Haleh had nothing to do with any of our democracy programs. She's pure and simple a scholar, not a spy."
Esfandiari was kept in solitary confinement, surviving by exercising for hours and, without pen or paper, writing a book in her head.
"If I tell you no, I knew from the beginning they would send me home, it's a total lie. You are in solitary confinement you start thinking: Is that going to be my future?"
Family and friends launched a worldwide campaign to win her release. Hamilton even wrote a letter to Iran's religious leader, Ayatollah Khameni.
"It made the plea on strictly humanitarian grounds to release Haleh. Nothing in the letter tried to get into the big questions between the U.S. and Iran," said Hamilton.
The pleas worked, and Esfandiari, unaware of the efforts on her behalf, was simply told one day that she could leave. Her mother was among those waiting for her.
"It was really amazing because I hadn't really dared dream about it," said Esfandiari.
Back finally in Potomac, Md., months after leaving home, Esfandiari says she's only now starting to come out of a nightmare.
"I am sure that in a month's time when I have enough distance, put enough distance, between myself and Evin, then I will realize what a tough time it was. At my age, eight months is a long time and it does leave its marks on you."