Expert on African American and American popular music from the 1950s to the present.
- The relationship between popular music and race in the United States.
- The history and legacy of the Sixties.
- The experience of Vietnam veterans.
- Co-author of We Gotta Get Out of This Place: The Soundtrack of Vietnam, Rolling Stone's 2015 Book of the Year.
- Author of A Change Is Gonna Come: Music, Race & the Soul of America, Uncut magazines 1999 Book of the Year.
- Long-time member of the Nominating Committee of the Rock and Roll Hall of Fame.