Night Ranger is an American rock band from San Francisco that gained popularity during the 1980s with a series of albums and singles. The band's first five albums sold more than 10 million copies worldwide. The quintet is perhaps best known for the power ballad "Sister Christian", which peaked at No. 5 in June 1984. After their success waned in the late 1980s, the band split up in 1989 and its members pursued other musical endeavours including group and solo efforts. Brad Gillis and Kelly Keagy teamed up with bassist Gary Moon and released an album without the other original band members in 1995, but the band soon re-united to release two new albums in the latter half of the decade. Despite the departure of original keyboardist Alan Fitzgerald and guitarist Jeff Watson, the band has continued to tour and remains very popular in Asian countries, particularly Japan.