They're the captains of defense, backing up the defensive line and "blitzing" the quarterback. Although the gridiron has seen outstanding linebackers throughout pro football history, only a handful of the greatest players have been enshrined in the Hall of Fame. Photo-driven and stat-filled, this middle-grade sports title for fans of the NFL showcases 11 linebackers, ranked by induction year, from Chuck Bednarik and Dick Butkus to Mike Singletary and Ray Lewis. Includes sidebars about the position's role and how it's changed over time.