Melinda French Gates says she never expected to write a book about transitions. But over the past few years, she’s gone through a divorce (from her ex-husband, Microsoft cofounder Bill Gates), left the $75 billion foundation the two founded back in 2000, and turned 60. Her new book, The Next Day, dives into each of these monumental changes—and more.

“You don’t get to be my age without navigating all kinds of transitions,” French Gates writes in the book’s introduction. “Some you anticipated and some you never expected. Some you embraced and some you resisted. Some you hoped for and some you fought as hard as you could.”

In a recent interview with Fortune, the philanthropist explained that the idea for the book was born out of a commencement speech she gave at Stanford University last year, which focused on managing life’s twists and turns.

“I realized, ‘Gosh, I have a lot more to say about transitions,’” says French Gates. “So I just started to go ahead and do a book.”

French Gates is uncharacteristically candid in The Next Day.

“I loved Bill,” she writes in a chapter titled “Distill Your Inner Voice,” which details the end of her nearly 30-year marriage. “Not only that, but I valued our family life deeply—and I felt enormous responsibility to the foundation we’d started together. Was I going to rip all that apart? Was I going to forgo the future we’d imagined for so long?”

French Gates tells Fortune she was acutely aware of the ripple effects her divorce would have, both personally and professionally. That’s why, back in May 2021, before publicly announcing their split, the former couple made an important phone call—to none other than Warren Buffett, their friend and benefactor. (Over the years, Buffett has given more than $39 billion to the Bill and Melinda Gates Foundation, including donations he made after the couple decided to divorce.)

“I mean, he had made this enormous investment in the foundation,” says French Gates, “and so whatever decision he would eventually need to make or not make about that was his. We both felt strongly he was one of the first people we needed to tell.”

The Next Day is French Gates’s second book and her first that’s largely autobiographical. It also includes chapters on French Gates becoming a mother and the loss of a close friend earlier in her life. But the philanthropist says she felt obligated to write about her divorce.

“I felt like it was important to include it, because people knew I’d been through it,” she says. “And if I’m talking about transitions and I don’t write about it, then it feels disingenuous, right?”

Pivoting from the Gates Foundation to Pivotal

Last year, French Gates initiated yet another high-profile split. In June 2024, she stepped away from the Bill and Melinda Gates Foundation, focusing her philanthropic efforts on Pivotal, an organization she’d started in 2015 which aims to advance women and families through investment, partnerships, and advocacy. (The organization rebranded as the Gates Foundation after French Gates resigned.)

French Gates said that her “North Star” at Pivotal is lifting up women and girls. But just as she’s learned to roll with the punches in her personal life, she said that the strategy of how to achieve this goal requires an open mind rather than a set ideology—a point she makes in the book.

“The world for women is changing, so I need to have a lot of flexibility to know, ‘Where do I make investments? Where do I put down grants? Where do I use my voice?’” she explained in the interview, referring to both geopolitical and economic shifts.

Another point French Gates makes in the book is that the move to a full-time focus on Pivotal represented the first time in her philanthropic career that she had full control over how an organization’s resources are used. This, she said, has changed her as a leader in some unexpected ways.

“I think I ask more often, ‘Am I wrong here? What am I not seeing? What should I see?’” she said. “I’m probably able to be more vulnerable than I felt I could be at the foundation, and that was nobody else’s fault at the foundation. That was me.”

French Gates, who has long been known for her polished and privacy-conscious image, has become more comfortable with being vulnerable in other ways, too. One of the more surprising disclosures in the book is her openness about her recent struggles with panic attacks.

“I didn’t even really know if it was a real thing, and I never expected it to happen to me,” says French Gates. “But once it did, the more I started to talk to friends about it a little bit, the more I started to realize more people were having them than I realized.”

French Gates says the panic attacks were her body’s way of trying to tell her something—a signal that her head and heart were out of alignment. But these days, a bit of lingering uncertainty doesn’t seem to throw her inner voice out of whack.

As French Gates writes toward the end of her book: “I still haven’t reached the other side. But this journey has renewed my faith that even on our darkest, most difficult days, somewhere deep within us, a new beginning is quietly forming.”

Melinda French Gates explains why her new book focuses on big transitions, and why Warren Buffett was one of the first to learn about her divorce