Green Day: Billie Joe (vocals, guitar, mandolin, harmonica); Mike Drint (vocals, Farfisa organ, bass); Tre Cool (accordion, drums, percussion). Additional personnel: Benmont Tench, Gary Meek, Mistress Simone. To debate whether or not Green Day truly was or is a punk band in the purest definition of the punk ethic now seems irrelevant. If nothing else, they're a pop band who can't seem to help but write good songs--in the case of WARNING, some really good songs. This album makes up for any missteps the band may have taken since the fluke success of DOOKIE. From the Katrina And The Waves groove of "Castaway" to the Beatles-esque harmonica on "Hold On," WARNING inspires a sense of musical deja vu that never crosses the line into out-and-out thievery. Hands-down, the most interesting track here is "Misery," which struts along with Doors-like quirkiness and goes through a progression of cultural movements that take instrumental turns in the form of deep strings, mariachi brass, and acoustic guitar melodies. If there's a warning to be found here, it's that Green Day has become a real band. Not very punk of them, but promising all the same.