Mark Obama Ndesandjo, the half-brother of President Obama, has self-published a book detailing the ugly side of their shared father.

The Associated Press reports that in "Cultures: My Odyssey of Self-Discovery," Ndesanjo "recalls alcohol-fueled beatings meted out by his father to his mother. He recounts one incident in which his father held a knife to his mother's throat because she took out a restraining order against him."

Barack Obama Sr., who was married four times, was a Kenyan graduate student in Hawaii when he met President Obama's mother, Stanley Ann Dunham. Obama Sr. and Dunham were married for three years, having one child, Barack Jr. After their divorce, the senior Obama returned to Kenya and married Mark Obama Ndesanjo's mother, Ruth, an American. The half-brothers did not know each other growing up, meeting first in 1988; Obama Sr. died in 1982 in a car accident at age 46.

Ndesandjo has previously said his father was abusive and wrote a novel that drew upon his experiences. "My writing has alienated some people in my family," he told the Associated Press.

After growing up in Kenya, Ndesandjo attended college in the U.S., getting degrees from Brown, Stanford, and Emory. He moved to China in 2001 and now lives in Shenzhen. He held a news conference about his book in Hong Kong on Thursday.

"I wanted to tell my own story, not let people tell it for me," he told the Associated Press.  "Cultures: My Odyssey of Self-Discovery" includes an appendix that lists a number of alleged factual errors in Obama's 1995 memoir, "Dreams From My Father."

According to Ndesandjo, the half-brothers have not been on the same page before. "Barack thought I was too white and I thought he was too black," Ndesandjo said of their first meeting. "He was an American searching for his African roots, I was a Kenyan, I'm an American but I was living in Kenya, searching for my white roots."

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