Adele's 2009 debut album, 19, was a Grammy-winning smash hit that revealed the singer/songwriter's knack for bittersweet soul and folk-infused love songs that brought to mind an infectious mix of Dusty Springfield and Terry Callier. The album earned her a ton of fans, and interest was high for the inevitable follow-up. In many ways, her sophomore album, the similarly age-appropriate-titled 21, is a continuation of the sounds and themes Adele was working with on 19. She is still the bluesy pop diva with a singer/songwriter's soul and seemingly bottomless capacity for heartbreak. If the tastefully organic production and overabundance of well-known co-writers come off a bit too on-the-nose in terms of delivering to fan expectations, then the best thing the album does is to showcase Adele's titanic vocal ability, which -- more than a few times on 21 -- is simply spine-tingling.