The AC format has its origins in the arrival and eventual permanence of rock and roll as a music form in the United States during the late 1950s. According to Hyatt (1999), radio stations in the United States at that time wanted to keep airing current popular hits, a staple format that had already attracted listeners for decades. However, these stations did not want to play rock and roll and tried to find a way to keep the popular hits genre without having to play songs with a rock beat. Thus, they turned to popular songs that lacked the "heavy" sounds of rock and roll. These tunes became known by those in the radio industry as "easy listening" or "middle of the road." Hyatt refers to Adult Contemporary as being synonymous with both terms.

     Beginning in the 1960s, Billboard magazine created a new chart listing the top records considered easy listening and middle of the road, in addition to its pop, rhythm and blues, and country lists of popular songs. Billboard gave several names to this chart throughout the 1960s, which listed the top 20 (and during some years the top 15 to 25) singles. These names included "Easy Listening," "Pop-Standard Singles," and "Middle-Road Singles." By 1965 the magazine had settled on "Easy Listening" to describe the chart. Artists listed on this chart included music industry veterans such as Dean Martin, Frank Sinatra, Nat King Cole, and Andy Williams. By the late 1960s, folk artists such as Peter, Paul, and Mary and Simon and Garfunkel had hits on the "Easy Listening" list. The chart also included instrumentals by Herb Alpert and the Tijuana Brass, film composer Henry Mancini, and Mason Williams during the late 1960s and early 1 970s. Also during this period, Hyatt notes, "fewer people who considered themselves easy listening fans were requesting previous favorites like Frank Sinatra and Ed Ames." More notably, crossover between the "Easy Listening" and "Pop" lists started to occur at this time, with artists such as the Carpenters and Bread releasing mellow, rock-type songs that were listed on both charts.

     "Easy Listening" music grew in popularity; Billboard expanded the chart, lengthening the list from the top 40 singles to the top 50 in 1973. Keith ( 1987) points out that this genre appealed to the same type of audience who listened to stations featuring soft and mellow rock music. Additionally, during the late 1970s, the number of soft and mellow rock listeners declined as the disco format grew in popularity and as the number of hit music stations increased: "It was out of this flux that the AC format emerged in earnest" (Keith, 1987). Billboard renamed the "Easy Listening" chart in 1979, when it became known as" Adult Contemporary." During the next 14 years, the list's length fluctuated between 40 and 50 hit singles of the genre. In 1996 the chart came to list the top 25 singles ( Hyatt, 1999).

     During the 1980s, the AC format became the nation's most widespread, with its target audience encompassing the 25 to 49 age group, especially women, which made it appealing to advertisers as well. By the time of AC's maturation, its audience base consisted of adults who had composed the teen listenership of Top 40 radio in the early 1970s. AC, also referred to as lite or soft rock, drew in the thirty-something listener by offering "popular, upbeat music without the harshness that often accompanies rock" ( Keith, 1987). Typical artists with top AC hits during the 1980s included Lionel Richie, Billy Joel, Whitney Houston, and Phil Collins. Artists popular during the 1970s also hit the chart, such as Cher, Elton John, Barry Manilow, and Barbra Streisand.

     Regarding the programming of the AC format, stations that employ the genre place greater emphasis on the music, thus minimizing disc jockey chatter. AC stations might describe themselves as "soft rockers" or as "hot, soft, lite, bright, mix or variety"; the phrase "continuous soft rock favorites of yesterday and today" serves as a common line in promotional spots (Macfarland, 1997). The music mix itself combines temporary singles with hits from the past, though these generally do not include true "oldies." Called "recurrents," these older songs typically have just left the current chart and are usually between six months and two years old (Howard, Kiev­ man, and Moore, 1994). Halper ( 1991) contends that AC music directors must keep up with the newest adult pop artists, such as those presented on VH1, the slightly more mature version of MTV, the cable music channel.

     AC stations present chart toppers, both current and potential, and recurrents in blocks or sweeps, which can last as long as 28 minutes of uninterrupted music. Announcers usually follow these sweeps with recaps of song titles and artists, and commercials are limited to four or five per cluster (Macfar­ land, 1997). AC stations also may feature contests, all-request hours, programs that feature hits from a particular decade, and lifestyle-oriented news. As with other music-oriented formats, news takes a secondary position, although it is usually presented during drive time. Some stations feature strong on­-air personalities, especially in the morning, and an upbeat delivery style similar to the Contemporary Hits Radio and Top 40 formats.

     By the mid-1990s, AC came in second to the country as the most popular format in the United States, even though the number of stations featuring this format dropped between 1989 and 1994. Artists with hits on the Billboard AC chart during the 1990s included Mariah Carey, Michael Bolton, and previous hitmakers such as Elton John and Eric Clapton. AC hits of the late 1990s exemplified the soft/lite rock, "easy listening" sounds of early AC, a key characterization of this adult-oriented radio format, as embodied in the chart-topping singles of Canadian singer Celine Dion, who headed the list of all artists with songs spending the most weeks at number one on Billboard's AC chart (65, 19 of which were with one song [Hyatt, 1999]).