RALPH: The original meaning of the word Canon was a law or decree issued by the Christian Church; that's how Shakespeare uses it here. Later it also referred to the list of books which the church considered officially part of the Bible, like Genesis or Exodus.

SARAH: Finally, the term came to be able to refer a secular list of authenticated works. For example, the canon of Shakespeare means all the works that scholars attribute to him. You might think Shakespeare's canon would be simple to determine, but there are some plays that no one is quite sure of — for example Edward the III, which some, but not all, critics think Shakespeare wrote, or a play called Double Falsehood, which many now believe to have been a collaboration between Shakespeare and another playwright named John Fletcher.

RALPH: Even more recently, in the fields of literary study, "the canon" has come to refer to a set of works of Western literature considered to be of the highest quality and lasting value, and this has historically formed the basis for a liberal arts education.

SARAH: Defenders of this canon argue that such texts should still be the foundation of our education in the humanities, while a younger generation of teachers and writers have criticized the idea of a canon as representing only a narrow band of cultural perspectives. And as leaving out important voices, for example, the voices of women, and of cultures outside of Western Europe.