When Love Calls by Lorna Seilstad; historical fiction set in 1908.
The main character of the story leaves law school to care for her two younger sisters after their parents pass away. She takes a job as a telephone operator. It's very interesting reading about their training, and the strict rules they had to follow, such as mandatory church attendance, and no gentlemen callers during training. They also had to meet certain height and weight requirements.
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