Yvonne S. Thornton will be the keynote speaker at the commemorative service at 11:15 a.m. Jan. 20 at the Lied Center, the final event of the Martin Luther King Jr. Holiday Celebration.

Thornton, who lives in Teaneck, N.J., is board certified in obstetrics, gynecology and maternal-fetal medicine. She is Vice Chair of the Department of OB-GYN at Jamaica Hospital Medical Center in New York City.

She is the first black woman in the United States to be board certified in high-risk obstetrics.

Thornton received her medical degree from Columbia University College of Physicians and Surgeons and has risen to the rank of clinical professor of obstetrics and gynecology.

Thornton is also the author of the 1995 critically acclaimed biography, “The Ditch Digger’s Daughter: A Black Family’s Astonishing Success Story.”

The book was nominated for a Pulitzer Prize and was later the source for a made-for-TV movie. There are now more than 250,000 copies in print.

Thornton’s book tells the story of how the six daughters of a ditch digger took to heart their father’s simple philosophy: Excellence is the best antidote to racism.

Copies of Thornton’s book will be available for sale at the commemorative service, and there will be a book signing.