Their initial appearance (December 17, 1936) was so successful that the following year they were given regular cast roles as part of "The Chase and Sanborn Hour". Under various sponsors (and two different networks), they were on the air from May 9, 1937 to July 1, 1956. The popularity of a ventriloquist on radio, when one could see neither the dummies nor his skill, surprised and puzzled many critics, then and now. Even knowing that Bergen provided the voice, listeners perceived Charlie as a genuine person, but only through artwork rather than photos could the character be seen as truly lifelike. Thus, in 1947, Sam Berman caricatured Bergen and McCarthy for the network's glossy promotional book, "NBC Parade of Stars: As Heard Over Your Favorite NBC Station".