The moon has always cast a spell on Man. Because we live in a scientific age, we look for scientific explanations for this - the moon effects the tides, the menstrual cycle seems linked to the moon. These miss the point.
The werewolf legend isn't linked to any of these scientific justifications. Neither was the royal court of Ur, where the entire court was entombed alive with the dead king. There's something deeper, primitive.
The moon is unique in the heavens, in that it changes in a way that is obvious to the naked eye. Full moon, gibbous moon, half moon, crescent moon, new moon.
New moon. Why not "gone" moon, or "dead" moon, or "empty" moon?
The new moon is pregnant with symbolism - it's the start, not the end. The moon represents the cycle of time: planting and reaping, birth and death, spring and winter. For primitive man, it was time. The royal court of Ur didn't care that the moon was linked with the tides. They did care about the cycle of time, and birth and death - and rebirth - yea, even unto death themselves.
The picture is from NASA, the crescent moon and the crescent Venus (click to see the whole thing, it's quite striking). We can't know what the ancient Babylonians would think of this picture of the Moon and Venus/Ishtar, but we can imagine.
There is no Dark Side of the moon. We always see the same face - literally, the Man In The Moon, because tidal forces have locked the moon's rotation to the earth. There is a far side of the moon that we never saw until the lunar probes of the 1960s, but both faces go through light/dark day/night cycles.
At the time of the new moon, near sunset and sunrise, you can sometimes see the dark face weakly illuminated. This is called Earthshine, and is light reflected off the earth illuminating the moon. Light in darkness.
But this is wandering into the realm of science, too. The fear of the werewolf isn't explained by any of this. Instead, it's the battle of light vs. dark that is in each of our souls. With the werewolf, darkness has won, at least temporarily.
Mithra was a cult in ancient times, the only real competition to the new Christian religion - you find temples to Mithra all over the Roman empire, especially where there were army camps. The cult was explicitly about this battle of light vs. dark, and used even older symbols (that were still recognized in that day) as part of its sacred story. The Bull played a big part, which seems odd for us today. We've forgotten that the Bull was associated with the moon - the crescent horns are an image of the crescent moon. Ancient kings of Ur, as well as the Pharaohs explicitly referred to themselves as representatives of the Bull God. He who controls the cycle controls society.
The climax of the Mithraic ceremony was the sacrifice of a bull, the breaking through the cycle of time, the victory of light over darkness. The parallel to the Mass is striking. In both ceremonies, there is the turning point. Earthshine.
And so to the soul, or the psyche. There is light and dark in each of us, which waxes and wanes in a different rhythm. Depression is a perpetual state of the waning moon, of autumn, with no promise of spring. The new class of medications that have emerged in the last 20 years are a brake on the runaway waxing tendency. Restoring the cycle to balance.