A convincing argument that rock & roll doesn’t need reinvention in order to revive itself, Courtney Barnett’s full-length debut Sometimes I Sit and Think, And Sometimes I Just Sit. falls into a long, storied rock tradition but never feels beholden to it. By almost any measure, Barnett is a traditionalist — a singer/songwriter supported by a guitar-bass-drum trio, cranking out ballads and squalls of noise. Certainly, those flurries of six-string fury do recall a variety of indie rock from the ’90s, an era when there was a surplus of guitar-friendly singer/songwriters, and if Sometimes I Sit does occasionally seem reminiscent of Liz Phair‘s landmark Exile in Guyville, it also seems to go back even further, sometimes suggesting the twitchy nerves of the former pub rockers who cranked up the volume and sharpened their invective in the wake of punk. So, Barnett might be part of a long line of underground rock troubadours but, as always, what matters is her specificity. Barnett’s thick Australian accent carries an unstated pride for her homeland, but her sly twists of phrase, alternately wry and melancholic, give a greater sense of place, time, and character. Offhand observations mingle with understated insights, a nice trick of songwriting that the music cannily mirrors. When called upon, Barnett and her band can be furious — “An Illustration of Loneliness” and “Kim’s Caravan” both work themselves up to a knotty, gnarled head — but they can also slip into a soothing sadness (“Depreston,” “Boxing Day Blues”). Usually, they’re punchy but not precise, hammering the hard hooks of “Aqua Profunda!” and “Nobody Really Cares If You Don’t Go to the Party” into place, giving “Elevator Operator” and “Pedestrian at Best” an urgency that mimics Barnett’s cloistered, clever words. There are no frills here but there is a distinct, compelling voice evident in Barnett’s songs and music alike. That’s what makes Sometimes I Sit and Think, And Sometimes I Just Sit. so invigorating: it may have roots — perhaps even some inadvertent ones — but it’s music that lives thoroughly in the moment.