“Family stories are how we remember,” says Rita Williams-Garcia. And the memorable adventures of three young sisters during the tumultuous summer of 1968 were at the heart of her 2010 middle-grade novel, One Crazy Summer, a Newbery Honor Book and a National Book Award finalist. In the much anticipated sequel, P.S. Be Eleven, out this month from HarperCollins/Amistad with a 50,000-copy first printing, Williams-Garcia again looks at the changes sweeping the nation in the late 1960s through the eyes of a family going through changes of its own.

The new book “picks up where One Crazy Summer leaves off,” says Williams-Garcia. “We follow the girls back to Brooklyn, to their familiar surroundings, where they are reunited with family. But they walk into all kinds of changes.” Inspiration for this second installment came largely from “Delphine’s desire to know something more about love and her family,” the author says. “Her father is remarrying, and Delphine knows that he never married her mother, so she wonders if her parents ever loved each other.”

The author had not initially planned on doing a sequel—“absolutely not!” she says with a laugh. “But I really loved these girls. The more I understood why and how things happened [to them], I could see those scenes. Halfway through One Crazy Summer, I would make notes that said, ‘leave it alone, belongs in book two,’ because there was too much for just one book.”

Though readers learn more about Delphine’s journey, they also glean some history of the day, be it the effects of the Vietnam War on a relative or the girls’ Jackson Five fever. “My hope is that kids will ask their grandparents and aunts who remember that time in detail and who, in story, can tell them about their experiences,” Williams-Garcia says. The result can “maybe have more of an effect than reading it in a history book.”

The author plans to relive the era one more time with Delphine and her sisters in a “third and final book of the family saga,” Williams-Garcia says. “We’ve seen the girls and their mother and the Movement and the girls at home. Next, Delphine is going to be concerned with her family breaking up.”

Williams-Garcia signs copies of P.S. Be Eleven today, 10:30–11 a.m., at Table 9 in the Autographing Area. While at BEA, “I have to walk the entire floor,” she says. “I feel like a child on a sugar rush—I want to see everything and read everything.” She is especially thrilled when she spies books by her students at Vermont College of Fine Arts, where she teaches in the Writing for Children and Young Adults program. “We scream like it’s the Jackson Five!” she says.