Writing “A Time to Every Purpose: Letters to a Young Jew” took esteemed historian Jonathan Sarna out of his comfort zone. There’s not a single footnote to be found in its 200 pages.

That’s not to say the book doesn’t reflect Sarna’s exemplary scholarship. It’s just a lot more personal than his other books. After all, it’s written to his college-bound 17-year-old daughter Leah.

Sarna will be in town to talk about the book — and no doubt myriad other topics of Jewish interest — when he speaks this week at three events in San Francisco.

“A Time to Every Purpose” is the latest in the Perseus Books series, which included titles like “Letters to a Young Evangelical,” “Letters to a Young Activist,” and even volumes addressed to young journalists, golfers and chefs. The publisher asked Sarna to write one about and for young Jews, and had sent him a stack of past titles to peruse.

It was George Weigel’s “Letters to a Young Catholic” that most struck Sarna, who read it while waiting for a delayed commuter flight to take off.

“I was deeply impressed with it,” says Sarna, a professor of Jewish American history at Brandeis University in Waltham, Mass. “Weigel takes you on a tour of different Catholic shrines and uses those places as a way to explore what Catholicism is all about. I asked myself, how does one do that for Judaism?”

He realized that for Jews, time is more important than place. As soon as he pondered the holidays on the Jewish calendar, he knew he could use that as the jumping-off point to reach young Jews.

Sarna’s idea was simply to divide the 13 chapters among the Jewish holidays, and not just the well known ones like Rosh Hashanah and Chanukah. He would also include the less familiar like Tu B’Av (a festival which traditionally encouraged young, single women to “seduce” single men) and even totally unknown ones like Maimuna, a holiday celebrated primarily among Jews of Moroccan ancestry.

Even as encyclopedic a scholar as Sarna learned some new things with his latest book. For his chapter on Tu B’Shevat, he delved into new Jewish environmentalism, a far cry from the tree-planting holiday he remembered as a kid.

There was just one thing missing: an addressee.

Fortunately, when Sarna asked if his daughter would participate, Leah Sarna said, “I’m cool with it.” Each chapter in Sarna’s book begins with the words “Dear Leah” and ends with the words “Love, Abba” (Hebrew for “father”).

“I wanted to have somebody in mind,” he says of the writing process. “I think she contributed in significant ways. It was nice to give her every chapter and see how she commented. There were places where she thought this would not speak to people of her generation or I was being too preachy.”

Sarna admits Leah had a better Jewish education than many of her peers, and not just from attending Jewish day schools and summer camps. Her father also happens to be one of the nation’s preeminent Jewish scholars.

He has written more than 20 books, including “American Judaism,” which won the 2004 Jewish Book of the Year Award from the Jewish Book Council. Sarna is also the Joseph H. & Belle R. Braun Professor of American Jewish History at Brandeis and director of its Hornstein Jewish Professional Leadership Program.

Viewers got to know him recently with the 2008 PBS series “The Jewish Americans,” for which he provided on-screen insight and context.

Despite the academic credentials, Sarna says, “I do like writing books people can read. I never felt history is arcane and unreadable.”

Leah, his daughter, read “A Time to Every Purpose,” and appreciated it. But what about other Jewish young people who might find themselves reading the book?

“Instead of focusing on ‘Why be Jewish?’ I hope they will think of Judaism as a way of life, a way sanctifying time,” he says. “My goal is not necessarily to persuade them, but to inform them.”

“A Time to Every Purpose: Letters to a Young Jew” by Jonathan Sarna ($23, Basic Books, 200 pages)

Jonathan Sarna will speak 7:30 p.m. Sept. 4 and 6:30 p.m. Sept. 5 at the JCCSF, 3200 California St., S.F. The Sept. 4 lecture costs $10-$12, and the Sept. 5 lecture, which includes a kosher dinner, costs $35-$40. Information: www.jccsf.org/arts. Sarna will also kick off Congregation Beth Sholom’s David Levinson Memorial Speaker Series with an address

during 9 a.m. Shabbat services Sept. 6. The event is free at Beth Sholom, 301 14th Ave., S.F. Information: (415) 221-8736.