11/17/2010 01:12 pm ET Updated May 25, 2011

The Great Migration & 'The Warmth Of Other Suns': Isabel Wilkerson On The African American Immigrant Story

Between 1915 and 1970, 6 million African Americans left the only homes they'd known in the American South in search of better lives and opportunities in the North and West. Their exodus from hamlets and cities governed by Jim Crow laws is called the Great Migration and it's the focus of Pulitzer Prize-winner Isabel Wilkerson's new book, The Warmth of Other Suns.

Wilkerson spent 10 years interviewing thousands of people for her book. She frames the decision to leave the South as a defection, and sees the northern and westward migrations by African Americans as another wave of American immigration similar to those made by European emigres.

Wilkerson explains the similarities to Root Editor-In-Chief and Harvard professor Henry Louis Gates:

"I became obsessed with the idea of why do people do this. America is made up of people who came from someplace else. Even the Native Americans came over the Bering strait... America is what it is because people came from someplace else. And I love to be able to see the comparisons between what these people did. Why the left. Where they were. And the people who may have come over from Europe, or across the Atlantic in steerage, or crossed the Rio Grande.
People leave when life becomes untenable where they are.

Go to The Root to watch Wilkerson's three-part interview with Gates.