Owing to the mass of its documentation, Egypt gives many examples of discoveries of documentary and literary papyri. The papyrologists traditionally speak of 'archives' for documentary texts and 'libraries' for literary texts, a polarity which reflects the two fundamental branches of papyrology, namely documentary papyrology and literary papyrology. But is it epistemologically correct? Does this reflect reality? The situation is actually less clear: many ancient sets combined both documents and books. After presenting the archives and the libraries as evidenced by papyri, I will try to show examples of these combinations and expose the reasons that make them so difficult to detect, to the detriment of papyrology and of our understanding of ancient culture in general.