about finding out who was No. 1.

Its features, included biographical details on performs, flashbacks, album cuts and Kasem's "long-distance dedication" for listeners who wrote to dedicate songs to friends and loved ones far away.

Kasem, whose baritone was always friendly and upbeat, delivered these in his most sympathetic voice, warm enough to melt butter. "Dear Casey," he began, and would read an emotional letter from a listener who wanted to connect with an old flame, express regret to a new love or send wishes to a far-flung family member.

The first one, for example, was from a male listener who wanted to dedicate Neil Diamond's "Desiree" to a sweetheart named Desiree who was moving to Germany.

The show, originally three hours, expanded to four in the late '70s.

In many ways, evenas Top 40 radio moved from the AM to the FM dial and took on the name "Contemporary Hit Radio," "American Top 40" remained a throwback to the way the format was in the 1960s, with frequent number jingles ("Number 29!") and a fast-moving mix, though Kasem, in temperament, practically defined the laid-back hosts of the Me Decade. (The exception to the laid-back rule was a much-copied outtake, now readily available on the Internet, of Kasem exploding in anger over a long-distance dedication that succeeded an up-tempo record.)

The show inspired several imitators, including a television version, "America's Top 10," hosted by Kasem himself.

Kasem left "American Top 40" in 1988 over a contract dispute with ABC Radio Networks and signed with competitor Westwood One, for whom he started a