ABBA's 2nd non-album single, released on September 6, 1978. It was originally intended as the lead single from the group's upcoming Voulez-Vous album, but was eventually not included. However, it was included as a bonus track on the 1997 CD re-issue.
The recording sessions for "Summer Night City" began in early 1978. A 43-second ballad-style introduction to the song had been edited out to improve the overall quality, but nothing seemed to work. Allegedly, mixing the single took at least a week, far more than it took to mix any other track in ABBA's recording history. A reluctant ABBA decided to release the song as a single in September despite their disappointment with the track as it was. The group still performed the song live on their 1979 world tour, though with the original introduction that had been removed in the studio recording. The unreleased version with the extended intro was finally released as part of the box set Thank You for the Music.