Beverly Cleary, who enthralled tens of millions of young readers with the adventures and mishaps of Henry Huggins and his dog Ribsy, the bratty Ramona Quimby and her older sister Beezus, and other residents of Klickitat Street, died on Thursday in Carmel, Calif. She was 104.

The death was announced by HarperCollins, her publisher.

With “Henry Huggins,” published in 1950, Ms. Cleary, a librarian by trade, introduced a contemporary note into children’s literature. In a humorous, lively style, she made compelling drama out of the everyday problems, small injustices and perplexing mysteries — adults chief among them — that define middle-class American childhood.