There are several classes of alleged libraries, which if they have real existence must necessarily precede all others. These include the libraries of the gods, animal or plant libraries, Preadamite and Coadamite libraries and the alleged libraries of the antediluvian patriarchs. All of these may be included under the term antediluvian and the period subdivided chronologically into Adamite or Patriarchal, Preadamite, Prehuman (plant and animal libraries) and Precosmic (libraries of the gods)!

There is a considerable literature on the subject of antediluvian libraries (cf. Schmidt, Bibliothekswissenschaft, 1840, p. 67; Richardson in Library Journal, 15, 1890, pp. 40-44), but this term has been, until recently, used to include mainly libraries which were alleged to have existed from Adam to Noah. Modern explorations in comparative psychology on the one hand and comparative mythology on the other have however now brought to light many potential or alleged libraries from before Adam—not forgetting that this first ancestor of ours has quite recently been dated some sixty million years before the Christian era!