When the Swedish pop ingenue Lykke Li first arrived in 2007 at all of 21, she was an adorable little thing, singing and shimmying with gumption. Her debut album, 2008's Youth Novels, was as resolute and irrepressible as the best of her compatriots -- Robyn, Nina Persson, Jens Lekman, even ABBA. And she enchanted a few notables along the way, including the rapper Drake, who sampled her "Little Bit" for an arresting mixtape deep cut. But there was a chill in the music -- sax skronks, woozy keyboards, Kewpie-ish voice lurching to the brink of sadness -- that her co-conspirator Bjorn Yttling helped install to keep things from ever getting too cute....