He is younger and sports a shaved head and a gold stud in his left earlobe, but the slim build, the loping gait and the high-set cheekbones give him a striking resemblance to his more famous half-brother, President Obama.

Mark Okoth Obama Ndesandjo, a 43-year-old businessman and musician, has lived in southern China for seven years, the last one assiduously attempting to avoid publicity. But he broke his silence yesterday, making a public appearance to publicize an autobiographical novel.

The self-published From Nairobi to Shenzhen follows Ndesandjo's peripatetic life. He was born in Kenya, the son of Barack Obama Sr., the same father as the president, and his father's third wife, Ruth Nidesand, the daughter of Jewish Lithuanian immigrants. The couple later divorced and Ndesandjo moved to the United States, earning degrees in physics from Brown and Stanford universities and an MBA from Emory University. He was married last year to a Chinese woman from Henan province.

As with the president's best-selling memoir, Dreams of My Father, Ndesandjo's book delves into growing up as a mixed race child and of a psyche shaped by an erratic father.

"My father beat my mother, and my father beat me," Ndesandjo told the Associated Press in an interview released yesterday. "I remember situations when I was growing up, and there would be a light coming from our living room, and I could hear thuds and screams, and my father's voice and my mother shouting."

At a news conference in Guangzhou, organized by the U.S. Chamber of Commerce for Southern China, Ndesandjo said it took a long time before he became "proud to be an Obama."

He said he wrote the book in part to exorcise the bad memories of his childhood and to publicize the issue of domestic violence. He said he plans to donate 15 percent of the proceeds of the book (published by Aventine Press, a self-publishing company based in San Diego) to a charity for children.