Leigh Giangreco is a D.C.-based reporter.

On a damp February day, the first floor of the Human Rights Campaign headquarters is bright and bustling with a gaggle of kids and their parents gathered in the lobby, umbrellas and petitions in hand.

The children, both transgender and cisgender, want to deliver a letter signed by 700 parents of trans youth to Education Secretary Betsy DeVos expressing their concern about the Trump administration’s position on transgender rights. When the Human Rights Campaign’s press secretary, Sarah McBride, walks out of the elevator draped in a casual, fleece-lined cape with a coffee mug in hand, the group greets her like a movie star.

Who is Sarah McBride? A transgender activist who broke barriers at the White House.

McBride shot to national fame in 2016, when at 26 she became the first transgender person to speak at a national political convention. Four years earlier, she published her coming-out letter in the student newspaper at American University, where she had just finished her year as student body president. Her letter became a viral sensation and launched her career as a transgender advocate.

Now McBride has published a memoir, “Tomorrow Will Be Different: Love, Loss and the Fight for Trans Equality.” The book chronicles McBride’s coming out, her activism and her marriage to Andrew Cray, a transgender lawyer at the Center for American Progress — and her loss of Cray to cancer just four days after the wedding ceremony. The couple were married in 2014 in front of family and friends on the rooftop of their Northwest Washington apartment. In the memoir, McBride refers to Cray in the past tense, but in person she can’t help slipping into the present tense. When a mother in the Human Rights Campaign lobby mentions him, McBride responds, “He is . . . ” Then she pauses for a moment. “He was . . . the best.”

Cray pushed for legislation protecting transgender patients from discrimination, including a rule issued in 2014 by then-Mayor Vincent Gray to ensure that transgender Washington residents have full access to health care and transition-related care. Cray also shepherded a regulation contained in the the Affordable Care Act that protects transgender patients from discrimination in federally funded health-care programs nationwide. The legislation addressed the fear McBride and Cray felt during his cancer treatment at Johns Hopkins Hospital in Baltimore. Though Cray never faced discrimination during his time there, McBride hesitated to bring him into a hospital whose former chief of psychiatry, Paul McHugh, had closed down the institution’s work on transition-related care and disparaged trans people.

More than three years after his death, Cray remains a constant presence in McBride’s life, as the silver wedding band on her left hand attests.

“I am perpetually asking myself ‘What would Andy do?’ every single day and with probably every single decision I make,” McBride says. That keeps the relationship intimate, she says, even though he has now been gone longer than the time they were together. “There was so much relationship and so much love in a relatively short period.”

To write her memoir, McBride mined years of Facebook posts, reflected on her memories, and interviewed friends and family. Some experiences — such as her historic debut at the 2016 Democratic National Convention — were still fresh in her mind when she started writing the book in January of last year. Her fight for the Gender Identity Nondiscrimination Act of 2013 in Delaware also came back to her with surprising clarity.

Remembering her time with Cray allowed her to grieve a second time, though it wasn’t the trauma from his cancer that hit McBride the hardest. Until she wrote the book, she had not meditated on the positive memories she shared with her husband. “That was really challenging,” she says, “because it was such a clear reminder of who wasn’t here anymore and sort of reexperiencing that feeling of loss of that relationship and that person.”

Cray had joked that he wasn’t “ready for this ‘Walk to Remember’ s---,” and the couple’s life never comes off as saccharine. Beginning with their meet-cute in 2012 at a White House event for LGBT pride month, this love story of two idealistic young advocates in Washington is more suited for an Aaron Sorkin rom-com than a Nicholas Sparks novel. But it does tug on the heartstrings; Cray’s life was infused with facing and overcoming fear, first that society would not accept his true self and again when he battled an unrelenting disease.

Though she isn’t shy about praising her late husband, McBride maintains that she isn’t trying to canonize him. Like any couple, she says, the two could bicker and act insensitively toward each other. But she knew that sharing her husband’s story, beyond his fight against cancer, was a way for him to live on.

“He was the best person I’ve ever known, and I want people to know someone who I think deserves to be known for their work, their goodness, their grace,” she says.

While “Tomorrow Will Be Different” is the story of McBride’s journey, she admits that the idea of writing a memoir at age 27 seemed self-indulgent or absurd at first. Yet just as she had after writing her letter at AU and advocating for transgender rights in the Delaware legislature, McBride discovered that putting a face on her cause could push her policies better than statistics.

“I think for me [the memoir] has defined the way I approach advocacy . . . that at the core of this has to be personal stories,” she says. “My job is not to necessarily articulate the most cogent case but rather the most compelling case, and that is done through people understanding the hopes, dreams and fears that transgender people have that are shared with really everyone.”

McBride’s book comes at a time when many Americans — and not just those in the transgender community — are feeling demoralized and disenfranchised. It’s tempting to believe that the last election scraped away what was just a thin patina of tolerance in this country and that the night in 2015 when the White House basked in a rainbow glow was nothing more than a flicker in the darkness. But in a world where the most vitriolic voices often sound the loudest, McBride’s story reveals that most people are not prone to hate.

Throughout the book, she acknowledges that her race, class, family support and political connections have often sheltered her from some of the worst discrimination other transgender people face, particularly those of color. She enjoyed a safe harbor when she came out that others often don’t, particularly on the liberal campus of American University in Washington.

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That’s heartening, but McBride is more inspiring when she shares stories of people who accepted her when she landed outside her comfort zone. When she applied to legally change her birth name at a Delaware courthouse, McBride expected hostility from the judge and those in the courtroom. Instead, the judge honored her request with a smile, and several people in the court offered her celebratory handshakes.

“That experience with that judge, but frankly the experiences that I’ve had across the board, have confirmed to me that when you can put a face and a name to something, most people will do the right thing,” McBride says. “ When you force someone to think about something in human terms and the lives that are truly affected, most people will come to the right decision.”

The young transgender children McBride met with at the Human Rights Campaign headquarters represent a new, more confident generation of activists. When McBride was writing the final chapter of her memoir, she racked her brain for what gives her hope for progress in the face of opposition. Her answer came in today’s transgender youth, who, unlike a young McBride or Cray, are able to live their dreams while embracing their identity.

“What my experience with Andy underscored was that hope only makes sense in the face of hardship and that all of us can bear witness to acts of amazing grace,” she says. “It is what I get to see every single day in my job, these young, transgender people who hold in one hand the knowledge of all of the hate that exists in the world but who hold in the other the knowledge that their identities are worth celebrating and that their lives matter.”

Tomorrow Will Be Different

Love, Loss, and the Fight for Trans Equality

By Sarah McBride

Crown Archetype. 273 pp. $26