Unreleased in the U.S. until 1995, the 1972 set Ring Ring captures ABBA in their earliest formative stages. The album’s tracks have a buoyant Europop feel, full of zest and sparkle. You can hear the classic ABBA sound coming together in “People Need Love,” the first tune that Benny Andersson, Bjorn Ulvaeus, Agnetha Faltskog, and Anni-Frid Lyngstad recorded as a foursome. The album’s title track—a huge hit across Europe—solidified ABBA as an entity and paved the way for their eventual Stateside success. Besides these key tunes, Ring Ring is worth hearing for its general tunefulness and semi-naïve sweetness, whether the style veers toward wistful folk-pop (“Another Town, Another Train”), old-fashioned adult pop (“I Am Just a Girl”), or nostalgic bubblegum (“Me and Bobby and Bobby’s Brother”). Of special note is the ballad “Disillusion,” a solo showcase for Faltskog. Overall, there’s a sense of a quartet just beginning to hit their stride as international hitmakers. (The deluxe edition offers an intriguing assortment of B-sides, alternate versions, and pre-ABBA rarities, including the L.A.-style country-rock tune “Santa Rosa” and the folksy Bjorn/Benny release “Hej Gorle Man.”)