 Influenced by 1960s rhythm and blues, soul, bluegrass, and rock bands such as the Byrds and Buffalo Springfield, the Eagles' overall sound has been described as "California rock".In the words of Sal Manna, author of the CD liner notes of the band's 1994 album "Hell Freezes Over", "no one knew quite what 'California rock' meant – except perhaps that, because in California anything was possible, music that came from that promising land was more free-spirited and free-ranging.