Why demeter...
Bust of Isis-Sothis-Demeter. White marble, Roman artwork, second part of Hadrian's reign, ca. 131--138 CE. From the gymnasium in the Villa Adriana, near Tivoli, 1736. This image can be found at Wikimedia Commons.
The image on the cover is a statue of a goddess restored as Demeter from the Vatican Museums, Vatican City. It is a Roman copy in marble after a Greek original from ca. 420 BC.