<P> The International Companion Encyclopedia of Children's Literature notes that "the boundaries of genre...are not fixed but blurred". Sometimes, no agreement can be reached about whether a given work is best categorized as literature for adults or children . Some works defy easy categorization . J.K. Rowling's Harry Potter series was written and marketed for young adults, but it is also popular among adults . The series' extreme popularity led The New York Times to create a separate best - seller list for children's books . </P> <P> Despite the widespread association of children's literature with picture books, spoken narratives existed before printing, and the root of many children's tales go back to ancient storytellers . Seth Lerer, in the opening of Children's Literature: A Reader's History from Aesop to Harry Potter, says, "This book presents a history of what children have heard and read...The history I write of is a history of reception ." </P> <P> Early children's literature consisted of spoken stories, songs, and poems that were used to educate, instruct, and entertain children . It was only in the 18th century, with the development of the concept of childhood, that a separate genre of children's literature began to emerge, with its own divisions, expectations, and canon . </P> <P> French historian Philippe Ariès argues in his 1962 book Centuries of Childhood that the modern concept of childhood only emerged in recent times . He explains that children were in the past not considered as greatly different from adults and were not given significantly different treatment . As evidence for this position, he notes that, apart from instructional and didactic texts for children written by clerics like the Venerable Bede and Ælfric of Eynsham, there was a lack of any genuine literature aimed specifically at children before the 18th century . </P>

What is the history of children's literature
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