Photographer Robert Frank and Sarah Greenough, senior curator and head of the department of photographs, National Gallery of Art. Looking In: Robert Frank's The Americans, an exhibition organized by the National Gallery of Art, is the most comprehensive and in-depth exploration of the single most important book of photographs published since World War II. In this podcast of the annual Elson Lecture, recorded on March 26, 2009, Greenough speaks with the renowned photographer about his career before, during, and after The Americans.