(Jessica Hill/AP Photo)

Hillary Clinton seems to have been enjoying her downtime since leaving the State Department. She takes long walks, spends time with her dog and, according to an interview in People magazine, has even been "binge-watching" the Netflix TV series, "House of Cards."

But don't be too fooled. Amid this seemingly "leisurely" schedule, Clinton has been working hard on her fourth book, "Hard Choices," which will be released next week.

Clinton first announced she was embarking on the book, a memoir about her time at the State Department, in April 2013, just two months after stepping down as secretary of state.

"It was that or eating bon-bons," Clinton joked recently.

Clinton spent the next year working on the roughly 650-page book - a laborious and sometimes amusing process, which she has recounted in appearances and interviews over the past few months.

"[I] dragged the manuscript I was working on with me everywhere I went - including on vacation," she recalled in a video released last week by her publisher, Simon and Schuster.

Doing so was a "godsend," Clinton said, because on one of those trips she had the idea to begin the memoir by talking about the end of her 2008 campaign and then the "unlikely journey" that led her to accept the role of secretary of state.

Most of the book, however, was written in Clinton's home in Chappaqua, New York - specifically, in her "cozy" study on the third floor that used to be the attic of an old farmhouse.

It was up there, Clinton has said, that she "toiled away" for months, writing "barrels and barrels" of drafts by hand.

"If you did see my study at home," she told a group of publishers in March, "you would think it was an episode from 'The Hoarders.' The notes, the pages, the drafts … it's amazing."

Carolyn Reidy, one of Clinton's editors, echoed the sentiment at the event in Midtown Manhattan: "She revises, and then revises again."

This is not Clinton's first literary effort. She penned "It Takes a Village: and Other Lessons Children Teach Us," about her vision for children of America, in 1996, followed by "An Invitation to the White House: At Home With History" in 2000 and "Living History," the memoir of her years as first lady, which was published in 2003. But even with three books behind her, Clinton said writing is still the hardest part of the process.

Over the past year, Clinton sought editorial advice and encouragement from close friends and family, including former President Bill Clinton, their daughter Chelsea, her editors, Ready and Jonathan Karp, and some former staff members.

Joking about her husband's guidance in March, she said the biggest challenge there was deciphering his handwriting.

In a letter from the publisher released by Simon & Schuster on Tuesday, Jonathan Karp said that Clinton, "through multiple drafts," addressed "every topic I raised while working on the manuscript."

At the end of the day, however, Clinton said what ended up inside the book was up to her.

"I had a great team that I could never have done it without," she has said. "But ultimately, I had to take responsibility for every word. I had to be the one who decided how I wanted to describe a situation … how to connect it with people here at home."

The memoir will touch on issues ranging from "climate change to Crimea." It also includes a 34-page chapter, reported last week by Politico , devoted entirely to the attacks in Benghazi, where Clinton offered a rebuttal to her critics.

"A light summer read," Clinton has often joked. "Great for the beach."

Clinton turned in her final manuscript in April 2014 - one year after she made the initial announcement a book was coming.

She told a group of women at a leadership conference in Boston at the end of last month, "I literally have just turned in my book, so if I look even more tired than usual it's because I am."

After debating various options for book titles - including one her favorite submitted suggestions, "The Scrunchie Chronicles: 112 Countries and It's Still All About My Hair"- Clinton finally landed on "Hard Choices."

"In the end," Clinton said recently at an event in Washington, D.C., "I felt that pretty well described my experiences on the high wire of international diplomacy and what it takes to protect America, our interests and our allies in a dangerous world."

Before embarking on a nationwide book tour this month, Clinton will sit down with ABC News anchor Diane Sawyer for her first television interview in conjunction with the release. The interview will air during a one-hour ABC News primetime special on Monday, June 9, at 9 p.m. ET.

ABC News' Robin Roberts will follow up with Clinton's first live interview, on Tuesday, June 10, on "Good Morning America."