An American rock band which first found success in Canada and later in the USA and worldwide. There have been 3 primary lineups over the group's four-decade history, with the constant centre of the group since 1974 being sisters lead singer Ann Wilson and guitarist Nancy Wilson. They rose to fame in the mid-1970s with music influenced by hard rock and heavy metal, as well as folk music. Their popularity declined in the early 1980s, but the band enjoyed a comeback starting in 1985 and experienced even greater success with album oriented rock (AOR) hits and hard rock ballads into the 1990s.