Isabel Wilkerson's excellent new book, The Warmth of Other Suns: The Epic Story of America's Great Migration, has garnered a great deal of press in recent weeks.
Researchers wishing to examine a wealth of primary source material on the living and working conditions of African-Americans in this era might want to take a look at a fascinating microfilm collection titled "Black Workers in the Era of the Great Migration, 1916-1929," housed in Green Library's Media-Microtext. Edited by by James Grossman, the set compiles records from various Federal agencies and departments--ranging from the U.S. Coal Commission and Bureau of Employment Security to the U.S. Children's Bureau and Bureau of Agricultural Economics. A guide is also available, with a short introductory essay.
Additionally, as David Oshinsky noted in the opening paragraph of his review of Wilkerson's book, the Chicago Defender is another invaluable primary source of the African-American migration out of the South. Stanford researchers can access the full-text archive of the Chicago Defender, a title in the ProQuest Historical Newspaper series.