"It turns out Californication was only foreplay. With the accomplished, insanely melodic By the Way, the Red Hot Chili Peppers dive headfirst into the pop realm that their 1999 single “Scar Tissue” hinted at. They swim around in the same inviting Southern California waters that inspired the Beach Boys, and discover that the incandescent hook can say as much as, if not more than, the testosterone-driven backbeat.

A near-perfect balance of gutter grime and high-art aspiration, the Rick Rubin-produced By the Way continues the Peppers’ slow-motion makeover. The band pioneered the funk-rock-rap hybrid thing in the Eighties, and then, beginning with BloodSugarSexMagik and its single “Under the Bridge” in 1991, began moving away from the genre’s stultifying repetitions. Slyly, without doing anything drastic to alienate their core audience, the Peppers have shed their early devices — the jerky raps, the faux-P-Funk rhythms — that were once innovative but quickly became the stock tools of every rap-metal hybrid in the land. Along the way, the Peppers’ songs got more intricate, acquiring string riffs and heroic guitar counterlines, and pretty soon this band of loutish love thugs became the alt-rock Aerosmith (minus the screeching-and-beseeching power ballads), creators of music that could be at once credible and commercial. The transition has been so gradual that those who were on the scene in the rowdy Eighties followed right along and stayed as the band made its lunge toward art..."

- Rolling Stone