A teenage Laura Marling first grabbed attention with songs she posted online, and she released her debut album at 18. But her music really harks back to the pre-Internet era: She writes subtle tunes and poetic lyrics that need to be absorbed the old-fashioned way—over multiple album spins. The production also sounds vintage, with acoustic guitars upfront, and drums used only when absolutely necessary. And if her delicate high register doesn't remind you of early Joni Mitchell, the sophisticated chord changes probably will.