t's time to start taking Jenny Lewis seriously. Probably we should've started a long time ago -- around 2002, when her band Rilo Kiley released The Execution of All Things (still, I think, their best album). But she was a former child actor. She did have The Wizard, Troop Beverly Hills and Foxfire to live down. In fact, it might have been The Wizard -- and the cutesy songs on Rilo Kiley's first couple CDs, songs like "The Frug" and "Bulletproof" -- that made Lewis an ironic indie heartthrob first and a serious musician second. The Nintendo girl who kissed Fred Savage? Grew up to be in a decent indie rock band? And to be, like, sexy? A pasty indiethustiast's dream.

Because of their precious indie rock pedigree, it's sometimes hard to tell if Rilo Kiley is serious or not; especially their most recent album, Under the Blacklight, seemed like a weird detour away from earnest, rough-around-the-edges rock into slick pop. Lewis' second solo album, however, is less ambiguous. Her first outing without Rilo Kiley was monochromatic -- modest agnosti-gospel songs with countrified backing vocals -- but Acid Tongue is determined, substantial and, above all, confident.

Lewis has turned in her strongest batch of tunes as a songwriter, and her vocal delivery has matured to the point where she seems to be controlling her vocal chords rather than the other way around. Her guttural emotion sometimes got the better of her on early Rilo Kiley releases, but more typical of Acid Tongue is the way, on "Pretty Bird," Lewis' voice lilts, hovers and slowly dies, all in the span of one note.

Even without "The Next Messiah," a behemoth of a nine-minute suite, Acid Tongue is an ambitious album, from the bouncy, twangy "Carpetbaggers" to Lewis' weary confessional on the title track: "to be lonely is a habit / like smoking or taking drugs / and I've quit them both / but man, was it rough." The implication of "both" is that she hasn't, of course, quit being lonely, and although Lewis surrounds herself with able collaborators (including Elvis Costello), the overall impression is still one of solitude. The album ends with "Sing a Song For Them," which finds Lewis not serenading lovers or friends, but anonymous masses, "the never-made-its and the unrecognized," from bored housewives to homeless kids. These are songs, it seems, for those Lennon and McCartney called "all the lonely people."