There are certain riffs that are forever emblazoned in the soundtrack of rock and roll: the Beatles' "Day Tripper," the Stones' "Satisfaction," the Kinks' "You Really Got Me," Cream's "Sunshine of Your Love," Hendrix's "Purple Haze." Then there's the opening guitar lick to "Locomotive Breath," the inevitable showstopper at any Jethro Tull concert. Although Aqualung, the concept album featuring that little ditty, may be the disc that endeared Tull to the masses, the band possesses a lot more credence than any single song. But then they've always been somewhat misunderstood as well. For starters, JT isn't that leering frontman/flutist who makes a habit of balancing precariously on one leg. That would be Ian Anderson, who also assumes the role of singer, songwriter, and the group's sole constant since its formation nearly 40 years ago. (For the record, the band's name is derived from an 18th-century English inventor of agricultural tools.) Okay, so the tally of Tull players past and present rivals the number of times Florida's politicos have flip-flopped on property tax reform. But it's a hell of a band and has 11 platinum and five gold albums as proof it's doing something right. It also boasts a repertoire that freely mingles rock, folk, classical, blues, and literary observations with revelry and panache.