In 2001, Thomas Norman DeWolf received a tough lesson in genealogy. He found that his ancestor, U.S. Senator James DeWolf, died in 1837 as one of the richest men in America. Then, he found how the senator made his fortune: by spearheading the enslavement of 10,000 Africans, perpetuating the slave trade in America after it was officially outlawed, and personally murdering at least one slave. The revelation about the DeWolf family’s dark past sparked a journey that led DeWolf and nine cousins through the history of the American slave trade, from Rhode Island to Ghana, through Cuba, and back again. In Inheriting the Trade, DeWolf’s subsequent memoir, a modern family grapples with an inheritance of brutality­—and how to atone for their ancestors. “It’s going to take all of us digging much deeper beneath the surface of the issue of race-based oppression to understand the systemic nature of injustice,” writes De Wolf on his blog, “to repair what has been broken for centuries­—and remains so today.” DeWolf discusses and signs copies of his work at 7 p.m. at Olsson’s Books & Records, 418 7th St. NW. Free. (202) 638-7610.