After three albums as a major-label cult act, winning fans mostly on the road and through word of mouth, jam band Blues Traveler broke out in a big way with Four. Frontman John Popper’s virtuosic harmonica style was suddenly a pop sound, as the bouncy lovelorn plaint “Run-Around” became a long-running radio staple alongside alt-rock and dance singles. Blues Traveler exploited its mainstream-friendly side knowingly, with another key track here, “Hook,” critiquing the ingredients necessary to reel in a large audience. Though Four doesn’t display the adventurism of a Grateful Dead or an Allman Brothers Band, it shows plenty of affection for their styles, with the closing “Brother John” putting a jumpy, hard-to-pin-down rhythm to use and “The Mountains Win Again” shining light on a soaring slide-guitar line. The album ended up one of the most visible classic-rock-styled releases of its era.