Tarkington's second wife, Susannah, challenged her husband to "write about boys as they really are." She had brought to his attention a British book about student life at Harrow; Tarkington said "no boy ever talked like the puppets in that story." He set out to write realistic stories about boys like his nephews, or like he had been himself. The Penrod stories were the result.

He developed theories on childhood.

A child in the course of becoming an adult repeats the history of the human race from savagery to civilization. The period from eight to fourteen years is of pivotal importance in child development, he maintained in an article published in American Magazine in 1925, "What I Learned from Boys." Penrod, twelve at the time of his appearance in the stories, is nearing the end of this stage. He is essentially savage, but gives indications that this savagery is...