When John Mayer sings, "I will wait to find if this will last forever," on "Clarity," the opening track on his sophomore studio album, he could well be talking about his pop stardom. The 25-year-old singer-songwriter's 2001 debut, Room for Squares, went triple platinum and won him a Grammy earlier this year. But will he be the next James Taylor or the next Christopher Cross? Judging from Heavier Things, the jury is still out. While the disc confirms that Mayer is a lot more than just Jennifer Love Hewitt's ex-boyfriend, it lacks another killer single like "No Such Thing" or "Your Body Is a Wonderland" that would have cemented his standing as a major new artist built to last. Mayer still displays an easy way with a melody and a clever lyrical sensibility on these mostly midtempo numbers. He surrounds his guitar with a more full-bodied sound on songs such as the Dave Matthews Band-like "Bigger Than My Body." Mayer also experiments with horns on "Clarity" and the standout "Come Back to Bed," a retro-'60s soul ballad that nicely showcases his smoky vocals.