This showcases everything ABBA do so well. “Dancing Queen” might just be the greatest pop song ever recorded, and “Knowing Me, Knowing You” (ah-haaa) is a fine example of the kind of ballideering that would culminate a few years later in the most devastating and heartbreaking of break-up songs. It’s not a perfect album: songs like “When I Kissed the Teacher” and “My Love, My Life” are a bit dull in comparison to the classics of their type. The latter, in particular, I can now only visualise as being sung by the ghost of Meryl Streep in “Mamma Mia 2”.