When John Mayer emerged from the underground in 2001 with his debut album, Room for Squares, he was a little-known 22-year-old with an acoustic guitar and boundless energy. His ascent was rapid, powered by nonstop touring and intensive word of mouth, which reached critical mass just as radio and the video channels were discovering the young artist. Two years later, Room for Squares is now triple-platinum (the album remains in the Top 100 after more than 80 consecutive weeks on the Billboard Top 200 chart), spawning three hit singles, one of which, "Your Body Is a Wonderland," earned him a Grammy earlier this year for best pop vocal performance.Mayer's much-anticipated Aware/Columbia follow-up album, which bears the intriguing title Heavier Things, demonstrates how far this single-minded artist has come at this still-early stage of his career."In some ways," Mayer says, "the stakes get higher when you make a second major-label record and everyone's looking. And in some ways absolutely nothing is different, because your voice still sounds the same, and your hands still feel the same on the guitar. You just write your songs. You're just a guy with a guitar putting in a Thai food order at 9 p.m." The 25-year-old Mayer possesses a remarkable clear-headedness—fittingly, the new album opens with a song titled "Clarity"—and the rarefied level of consciousness that distinguishes this artist's songs has as much to do with their impact as his gift for melody, elevated musicianship or disarming personality. All of these elements, by the way, are present in spades on Heavier Things.The album was produced and mixed by Jack Joseph Puig, whose credits include Sheryl Crow, No Doubt, the Black Crowes, Hole and smart-pop progenitors Jellyfish."Jack understood what I wanted to do next," Mayer says of his decision to work with Puig. "We had met by way of friendship, not connections. I don't like pulling connections in; I'd much rather make friends. He understands the romance of making records. Jack and I pushed each other to the limits of our knowledge, and that's why the record is as fresh as it is. There are raw decisions made outside of the comfort zone of past achievement." Heavier Things was tracked in New York, Mayer's present home, and completed at Puig's longtime L.A. headquarters, Ocean Way. In addition to the lead single, the propulsive, hook-packed rocker "Bigger Than My Body," the album contains several songs Mayer has been performing live on his 2003 summer tour of amphitheaters and arenas, and they've become immediate crowd favorites. These include the poignant "Daughters," the smoldering, blues-based "Come Back to Bed," the evocative "Wheel" and "Something's Missing," which climaxes with a timely and ingenious things-to-do-today inventory.Mayer's longtime bass player David LaBruyere appears on all tracks apart from the virtually solo acoustic "Daughters," while keyboardist Jamie Muhoberac plays on eight. Guest musicians include legendary jazz trumpeter Roy Hargrove, drummers Matt Chamberlain, Steve Jordan and ?uestlove from The Roots, percussionist Lenny Castro and horn player Jerry Hay. Also present are guitarist Michael Chaves and drummer J.J. Johnson from Mayer's touring band."I came off the road after two years of straight touring and knew exactly what kind of record I wanted to make—it wasn't an accident," Mayer says of the process that led to the creation of Heavier Things. "I wanted to write songs this time that always felt good under my hands, no matter what. The only real criterion for the record was, 'Is it fun to play? Is it physically fun to feel the vibration of the strings or the feel of my throat when I'm singing it?' If an idea didn't meet that criterion, it got dumped. "This record is as different from the last one as I am from the last time I made a record," he adds. "What that amount is, I don't know, and I'm really interested to find out."DiscographyInside Wants Out (1999; reissued on Aware/Columbia in September 2002)Room for Squares (original Aware version released April 2001; Aware/Columbia final version released September 2001; certified triple platinum)Any Given Thursday DVD (February 2003; certified platinum)Any Given Thursday, (February 2003; certified platinum)Heavier Things (September 2003)Singles"No Such Thing""Your Body Is a Wonderland" (won 2003 Grammy for Best Pop Vocal Performance)"Why Georgia""Bigger Than My Body"