Bartlett Robinson

Perry Mason is a radio criminal serial based on the novels of Erle 
Stanley Gardner,and was broadcast on CBS Radio from October 18, 
1943 to December 30, 1955. The actors playing Mason changed
frequently during the shows run, beginning with Bartlett Robinson,
then Santos Ortega and Donald Briggs, before settling on John
Larkin, who portrayed the attorney until the end of the series
run. Della Street was played numerous actors including, Gertrude
Warner, Jan Miner, and Joan Alexander who was radio’s Lois Lane
on Superman. Sponsor of the show was General Foods, Tide.

Gertrude Warner with Santos Ortega (right) 

John Larkin