GWEN IFILL:

Forty-seven million people, or one out of every seven Americans, rely on government assistance to feed their families each month. For them, the $78 billion federal Supplemental Nutrition Assistance Program, long known as food stamps, is a lifeline.

Washington Post reporter Eli Saslow set out to trace that lifeline in a series of stories that took him far beyond the typical Washington lightning rod arguments. Yesterday, he was awarded journalism's highest award, the Pulitzer Prize in Explanatory Reporting, for his work.

He joins me now.

Eli, congratulations, first of all.