Brian Beirne was a radio DJ for KRTH-FM aka K-EARTH 101 in Southern California. He is known as "Mr. Rock N' Roll", which is his registered trademark and is considered one of the foremost historians on Rock N' Roll. Beirne's Los Angeles career lasted almost three decades, representing the longest continuous stint in FM radio history. Beirne was the voice of K-EARTH 101 during the RKO days and reached legendary status as a top-rating midday personality in the Los Angeles market for 27 years – a record-setting achievement in FM radio. His radio career has spanned 40 years which included San Francisco, Chicago, Cleveland, and Sacramento among others, and he continues to host and produce Rock and Roll shows around the country. Beirne retired from KRTH-FM on December 15, 2004.