Bono can’t be accused of skirting serious themes, but on “How To Dismantle an Atomic Bomb” his lyrics sometimes deal with them so abstrusely that it feels almost like a form of avoidance.

Despite the explosive title, the album is not a polemic but a meditation. The solution to “How To Dismantle an Atomic Bomb” is love, but never simply that. Love always swells into a metaphor or allusion for something bigger (or smaller): faith, science, politics.

Like Bill Clinton, Bono is “a little red and a little blue,” and faith is a central theme here. But rather than endowing him with an unshakable certainty and rectitude, it humbles him. Bono’s faith seems to be a struggle as much as a comfort.

The conversation with a higher power begins on “All Because of You,” a jangly song of thanksgiving and prostration: “All because of you / I am,” he sings. Just two songs later, on “Crumbs From Your Table,” he is making demands of that same power, pleading for something to renew his faith. “And you speak of signs and wonders / but I need something other,” he sings, “I would believe if I was able / I’m waiting on the crumbs from your table.” By “Yahweh,” the album’s prayer-like final track, he hasn’t settled his internal struggle, but come to terms with it: “Yahweh, Yahweh / always pain before a child is born / Yahweh, Yahweh / tell me now, why the dark before the dawn?”

Fans of U2’s early work will be pleased to find them circling back to their chimey guitar roots after the sometimes wayward experiments of the 1990s. “How To Build an Atomic Bomb” is filled with the Edge’s decorative guitar lines. But the album’s most affecting song is it’s simplest, both musically and lyrically. “Sometimes You Can’t Make It on Your Own” is built over a minimal, bell like guitar part that builds a slow momentum. Over the top, Bono sings about frailty in a quavering falsetto – it’s a tender moment of weakness from one of rock’s most self-assured personalities.

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If U2’s is substance highly stylized, Gwen Stefani’s new album is style without substance. Stefani is a pomo, multi-culti, fashionista. She is such a product of the now that the only words fit to describe her are neologisms and slang.

The way to understand her new solo album – “Love, Angel, Music, Baby” – is as a musical stroll down Canal Street. It’s a place where Chinese vendors sell knockoff Louis Vuitton handbags, beeping animatronic toys, pirated DVDs, and Baby Phat sweat suits side by side.

This is not entirely surprising coming from Stefani. Her band No Doubt emerged from the vari-cultural swirl of SoCal in the mid-1990s. Early songs like “Just a Girl” and “Spiderwebs” combined punk’s swagger, ska’s swing, and New Wave keyboards, and her aesthetic blended vato-gothic lettering and baby doll dress. As time has gone by, that cultural grab bag has only deepened to include Flamenco guitar, looping Jamaican dancehall, and Reggae.

But “Love, Angel, Music, Baby” takes her stylistic kleptomania to a whole new level: this is Stefani’s answer to the hip-hop album. Where No Doubt used mostly live instruments, Stefani here relies almost entirely on beats, and they come from some of the top hip-hop producers in the business: the Neptunes, Dr. Dre, and Andre 3000 of OutKast, to name a few. It’s the same approach Jay-Z took to “The Black Album”: Get in a room with a bunch of producers and see what clicks. The album’s themes also take their cues from hip-hop. Stefani name-drops her new clothing line (L.A.M.B.), brags about her considerable wealth, and taunts her detractors.

The album opens with “What You Waiting For?” – an infectious dance track about lack of inspiration (“take a chance you stupid ho,” she goads herself). But, as quickly becomes clear, she finds inspiration everywhere: in the Minneapolis sound of Prince and the Time, in the 1980s pop of Madonna and Cyndi Lauper, in the styles of her various collaborators.

“Hollaback,” starts with a booming computerized handclap beat that echoes Kelis’s hit song “Milkshake.” It’s no coincidence, as the Neptunes produced both tracks, but here the sound is softened with picked guitar and synthy trumpets. Stefani’s lyrics blend schoolyard imagery and mixed-sport metaphor. On lines like, “This sh-t is bananas / b-a-n-a-n-a-s,” she borrows the topsy-turvy lyrical style of Missy Elliot.

For “Crash” she apes the vocal sass and lo-fi production of multiracial Brooklyn trio Fannypack. “Luxurious” is almost a cover. It uses the same Isley Brothers sample (“Between the Sheets”) as Notorious B.I.G.’s “Big Poppa” and hews close to that song’s themes as well. Money, hos, and clothes is all Stefani knows.

But the most revealing track on the album may be “Harajuku Girls,” a tribute to the radically adventurous fashion of Japanese teenagers. She praises them for their “style detached from content/a fatal attraction to cuteness.” She might as well have been discussing herself.