Night Ranger is an American hard rock band from San Francisco formed in 1979 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 and have sold 17 million albums total. The quintet is best known for the power ballad "Sister Christian", which peaked at number five in June 1984.After their success waned in the late 1980s, the band split up in 1989, and its members pursued other musical endeavors, 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 reunited to release two new albums in the latter half of the decade.