Avery Clayton, the president of the Mayme A. Clayton Library & Museum in Culver City, California, recently discovered an unusual book in his late mother's extraordinary collection of African-American artifacts.

The small, cloth-bound book, titled Slave Songs of the United States, has a publication date of 1867 and contains a collection of 136 plantation songs. Could this be the first book of African-American spirituals ever published?

HISTORY DETECTIVES host Wes Cowan visits a music historian in Los Angeles to explore the coded messages and the melodies that laid the foundation of modern blues, gospel and protest songs of future generations. He also meets with Dr. James Norris, Director of the Howard University Choir for a special concert of selections from Slave Songs sung in the traditional style of mid-1800s spirituals.

17:40 segment.