If Arctic Monkeys launched a tentative retreat on Suck It & See, their first effort after being seduced by Josh Homme, the group once again forge ahead into bold new territory on AM, their fifth album. Neatly splitting the difference between the band's two personalities -- the devotees of barbed British pop and disciples of curdled heavy rock -- AM consolidates Arctic Monkeys strengths, a tricky task in and of itself, but the band pushes further, incorporating unapologetic glam stomps, fuzzy guitars, and a decidedly strong rhythmic undercurrent. At times, AM pulses to a distinctly danceable rhythm -- "Fireplace" percolates while "Why Do You Only Call Me When You're High" simmers and "Knee Socks" nearly rivals Franz Ferdinand in disco rock -- but this isn't an album made for nights out; it's a soundtrack for nights in. Too much of Alex Turner's mind is preoccupied with love gone wrong, jealousy, and general misanthropy, so even when he's singing about a "No. 1 Party Anthem," he's doing so with a nearly visible sneer. Such an undercurrent of cynicism makes AM an ideal album to listen to under the cover of darkness, but due to the Arctic Monkeys' muscular wallop and musical restlessness, it never feels like the band is wallowing in bleakness. Instead, this is vibrant, moody music that showcases a band growing ever stronger with each risk and dare they take.