How did Bob Newhart use one-sided phone conversations in his comedy?

Bob Newhart utilized one-sided phone conversations as a signature element of his stand-up routines, a technique he originally developed to alleviate the boredom of his office job by improvising characters with a friend.1

In these performances, Newhart assumed the role of an earnest, mild-mannered "straight man" engaged in absurd or wildly dramatic scenarios. By delivering only one half of a dialogue, he relied on his wry comic imagination and natural deadpan delivery to satirize the conformist nature of the era. This innovative approach was central to his debut album, The Button-Down Mind of Bob Newhart (1960), which became the first comedy recording to reach number one on the Billboard album chart and earned him a Grammy Award for best new artist.12