ALBANY, N.Y. (AP) — An expert on the true-life New York native whose story was told in the Oscar-winning film “12 Years A Slave” has written a new book on blacks who were kidnapped and enslaved in pre-Civil War America.

David Fiske’s book is titled “Solomon Northup’s Kindred: The Kidnapping of Free Citizens before the Civil War.” It hits book stores next week.

Fiske, who lives near Albany, has written two previous books on Northup, a free black musician who was lured south in 1841 with promises of work but instead was kidnapped and sold into slavery in Louisiana.

Northup spent 12 years as a slave before gaining his freedom.

Fiske’s new book focuses on the stories of other free blacks who were kidnapped and enslaved, and how economics and governmental actions made such crimes profitable.