Book excerpt: Sometimes a rock concert is more than just an event. Every so often a band's performance becomes a musical milestone, a cultural watershed, a political statement, and a personal apotheosis. On any given night a rock concert can tell the truth about who we are, where we are, and what's going on in music and life right now. In The Decibel Diaries, Carter Alan, longtime DJ and music director at WZLX in Boston, chronicles a lifetime in rock with a tour through fifty concerts that defined such moments - from Crosby, Stills, Nash & Young playing in the rain when Richard Nixon resigned to Talking Heads and the first stirrings of punk in the basement bars of New York and Boston to the bluegrass angel Alison Krauss and the adaptable veteran Robert Plant forging a plangent, plaintive postmodern synergy. For each event Alan shows us what it was like to be there and telescopes out to reveal how this show fit into the arc of the artist's career, the artist's place in music, and the music's place in the wider world. Taken together, The Decibel Diaries is a visceral and visionary portrait of nearly fifty years of rock 'n' roll.