For the Greeks, Demeter is an earth goddess; her name is De, which means earth (the same word as Gaia) and meter, which means mother. Demeter is the goddess of growing things, especially of grains like wheat and barley and millet.
Mythologically, Demeter is the sister of Zeus, Poseidon, Hades, and Hera, and so, like them, she is the daughter of Gaia, or Earth. This makes a lot of sense for a goddess of growing crops, because that is exactly what produces crops: earth.
D’aulaire’s Book of Greek Myths, by Edgar and Ingri D’Aulaire.
Greek Religion, by Walter Burkert (reprinted 1987). By a leading expert. He has sections on each of the Greek gods, and discusses their deeper meanings, and their function in Greek society.
Ancient Mystery Cults, by Walter Burkert (reprinted 1989). More about Demeter at Eleusis and other mystery cults.
Eleusis and the Eleusinian Mysteries, by G.E. Mylonas (1961).
Watch out! On Demeter, there are a lot of books which are more neo-pagan religion, or Freudian theory, than they are historical facts. The books we recommend have been selected for their strict historical accuracy.