Sheryl Gay Stolberg

In the fall of 2007, while helping her ambitious older half-brother, Barack Obama, campaign for president, Maya Soetoro-Ng holed up in the basement of the Obamas? Chicago home to pursue a long-held ambition of her own: writing a children?s book.

Obama was by then a best-selling author. But when he offered to introduce his little sister to his agent, Soetoro-Ng said, she refused. And she did not show him her book?a fictional paean to their mother, the free-spirited anthropologist Stanley Ann Dunham? until it sold to a publisher.

?That?s probably the stubbornness of a younger sister,? she said. ?We all want to find our own path.?

But the path she has chosen, in her family at least, is crowded. When Soetoro-Ng?s book, Ladder to the Moon, hit bookshelves, it added to a growing Obama family literary canon. President Obama, whose first two books earned millions, recently published a children?s book. His wife, Michelle, just signed a contract with Crown Publishing for a book on the White House garden, due in April 2012.

The first lady?s brother, the college basketball coach Craig Robinson, published a memoir last year. The president?s half-brother Mark Obama Ndesandjo, who lives in China, published a semi-autobiographical novel in 2009; another half-brother, George Obama of Kenya, last year published Homeland, an autobiography that chronicles his attempt to transform himself from drug-using gangster to advocate for Nairobi?s poor. Even the president?s mother has become a published author. In 2009, 14 years after her death, Duke University Press published her 1992 doctoral thesis, Surviving Against the Odds: Village Industry in Indonesia.

Soetoro-Ng wrote the foreword. Now 40 and the mother of two young daughters, Soetoro-Ng has been mostly out of the public eye since her brother?s election, living in Honolulu, where she is an assistant professor of education at the University of Hawaii. Suddenly, she is getting the kind of publicity ?appearances on the Today show and Piers Morgan Tonight, and a ten-city book tour?ordinarily reserved for movie stars or hot-shot novelists. So is it marketing? Something in the family genes? Probably a little of both, the author concedes.

?People are so curious still,? Soetoro-Ng said. ?They?re curious about my brother and his family, and I can?t really force my publicist to ignore that curiosity.?

She wrote Ladder in little spiral notebooks, between campaign stops. ?I did, of course, have my brother as an example, as someone who had literally taken pen to paper, because that was so much how he did things,? she said. ?And I think our mother definitely influenced us both. She was interested in stories, in storytelling.?

The Obamas, of course, are hardly the first book-writing presidential family. Elliot Roosevelt, a son of Franklin, published a series of murder mysteries (perhaps ghostwritten). Margaret Truman Daniel wrote fiction and nonfiction, after her father, Harry S Truman, left office. Jenna Bush, a daughter of George W Bush, wrote Ana?s Story, about her friendship with a woman who had HIV.

In recent years wives of presidents and vice presidents have often written books while their husbands were in office. Hillary Rodham Clinton wrote several, including It Takes a Village. Barbara Bush gave readers a peek into White House life through the eyes of her springer spaniel, Millie. Tipper Gore wrote a book about photography. Laura Bush wrote a children?s book with her daughter Jenna.

The difference with the Obamas, said the historian Doris Kearns Goodwin, is that the president was himself an accomplished writer before taking office?and his family members seem to have stories to tell. ?It?s not unusual for family members to write something,? she said. ?But in this case you?ve got an extended family from different parts of the world?even Michelle?s brother, coming from Chicago in sports?and you?ve got a writing family with Obama.?

Soetoro-Ng said she had long wanted to write a children?s book. She uses writing, she said, as a way to ?untie some basic knots in my own thinking??a task that felt more urgent after her daughter Suhaila was born in 2004. Becoming a parent, she said, forced her to confront the ?intense grief? that came with knowing her mother and her daughter would never meet.

She fixes that in Ladder, a whimsical tale in which Suhaila travels to the moon to be scooped up in the arms of her wise ?Grandma Annie,? who teaches her about suffering in the world. Its title comes from a Georgia O?Keeffe painting of the same name; when Soetoro-Ng was 9, she said, her mother gave her a postcard of the work.

Obama was not yet president when the Ladder manuscript arrived on the desk of Karen Lotz, the publisher and president of Candlewick Press. She said she was intrigued by Soetoro-Ng, though added that ?it would be disingenuous of me? not to say that she found it ?doubly fascinating because her mother was the mother of a presidential candidate.?

Soetoro-Ng, who says she wants to be ?judged on my own merits,? is already under contract with Candlewick to write a novel for young adults. ?My hope,? she said, ?is that I can continue writing and in the future I can just be Maya Soetoro-Ng.?