I have previously noted disdain for labeling athletes as "The Greatest of All Time." When it comes to radio D.J.'s, the assessment of greatness is easier to make. You do have to whittle it down to decades, eras, formats, etc.

I settled on the years 1954, when playing the 40 biggest hits began in earnest, and 1989, the the last year record sales determined the Billboard Hot 100, the last true year of 45 RPM record distribution, the infusion of club DJs and rappers on to air staffs.

The world changed, and so did Top 40/Contemporary Hit radio jocks. The comparison before and after would not be fair or accurate. So, here are 20 of the Greatest Disc Jockeys to open a mike over 35 important years, all but one in the nation's four biggest markets, in the format responsible for breaking hits, and the stations where they had their most success as Top 40 jocks:

1954-1964 

Alan Freed - WJW, Cleveland; WINS,New York

Art Laboe-  KPOP, KRKD, KRLA, Los Angeles

Murray the K - (Murray Kauffman) WMCA, WINS, WOR-FM, New York

Casey Kasem -  WJBK, Detroit; KYA, KEWB, San Francisco; KRLA, Los Angeles.

Dick Biondi -  WLS-AM, WCFL, Chicago; KRLA, Los Angeles

1964-1975

Dan Ingram -  WABC, New York

Cousin Bruce Morrow - WINS, WABC, New York

B Mitchell Reed -KFWB, Los Angeles, WMCA, New York

The Real Don Steele - KEWB, San Francisco; KHJ, K-100, KTNQ, Los Angeles

Robert W. Morgan - KEWB, San Francisco, KHJ, K-100, Los Angeles

Charlie Tuna - KHJ, KKDJ, KIIS-AM, KTNQ, KHTZ, Los Angeles

Wolfman Jack - XERF, XERB, Mexico; KDAY, Los Angeles, WNBC, New York

Big Daddy Tom Donahue - WIBG, Philadelphia; KYA, San Francisco

Larry Lujack - KJR, Seattle; WLS-AM, WCFL, Chicago

Chuck Leonard -WABC, New York

Bobby Ocean -  KGB, KCBQ, San Diego; KFRC, San Francisco; KHJ, Los Angeles

Dr. Don Rose - WFIL, Philadelphia; KFRC, San Francisco

1976-1989

Rick Dees - WMPS, Memphis; KHJ, KIIS, Los Angeles

Hollywood Hamilton -WHTZ, New York; KIIS-FM, Los Angeles

Jo Jo "Cookin" Kincaid - WXKS, Boston; KKLQ, San Diego

I've assembled this list at risk of omitting so many. I doubt anyone who has listened to stations that broke Hot 100 styled-hits in New York, Los Angeles, Chicago or San Francisco would fail to recognize these performers.

This format, and the era from which the list was derived, was not the most inclusive or diverse. Chuck Leonard was New York's first entertainer of color to cross from R&B radio to a major, mainstream station. Larry McCormick (better know as a TV news anchor at KTLA, until his passing in 2004) preceded him in L.A. by a year. In 1967, Walt Baby Love continued the progress at CKLW, Windsor, Ontario/ Detroit.

In the '70's, Women who had impact were Yvonne Daniels, overnight in Chicago at WLS-AM, Shana at KFRC, then KHJ; Liz Kiley did likewise at WABC. Renel broke the ceiling, in mornings, at KMEL-FM, San Francisco, in the 80's.