In general, a demon may be defined as a malicious spirit who does harm to human beings. In this sense, demons have been recognized since the time of the ancient Sumerians and Babylonians.

The culture of the Mesopotamian valley was particularly rich in demon lore. Demons were usually the spirits of natural forces such as fire, plagues, droughts, infant crib death, and diseases, and often took the form of fantastically-shaped creatures made up of a conglomeration of parts from dangerous or dreaded living things such as scorpions, serpents, lions, hawks, and so on. For example, Pazuzu, the Sumerian demon who attained celebrity status after his cameo appearance in the horror film The Exorcist, is a demon of disease who has four wings, the clawed feet of a hawk, and a snarling lion-like face.

The Mesopotamians viewed themselves as under constant attack from demons on all sides. Their only recourse was to fight against them with magic. They placed special bowls inscribed with potent word charms upside down under the foundations of their houses to catch demons and prevent them from entering the houses through the ground. They also made amulets with avertive verses against specific demons, such as those that might threaten the life of women during childbirth.

During their period of Babylonian captivity, the ancient Hebrews absorbed many Sumerian demons into their own folklore, and over time these were transmuted into uniquely Jewish demons, such as Lilith, the demon who strangles children in their cribs and visits solitary men in their beds to provoke nocturnal emissions. Lilith began her life as a class of Babylonian demon known as the lilitu.

In addition to the direct personification of the forces of nature, demons were formed by the vilification of the gods and goddesses of other cultures. Many of the medieval demons mentioned in the Old Testament, such as Ashtaroth and Baal, are the gods of Middle Eastern peoples other than the Hebrews.

The modern concept of demons owes many of its key features to the influence of Christian folklore and theological doctrine, which were heavily influenced by Jewish beliefs through the Old Testament. In Christianity, a demon is not just a malicious spirit, but a spirit of hell sent to Earth by the Devil to enforce his authority or to carry out his purposes.

Just as angels are the agents of God who act with divine authority to do good works among men, so demons are the agents of Lucifer who act with infernal authority to do works of evil. Indeed, in Jewish, Islamic and Christian mythology, Lucifer was himself once an angel of heaven who defied God.

Seeking to overthrow God and rule heaven, Lucifer assembled an army of apostate angels and initiated a war in heaven. He and his angels were defeated by Michael and the angels who remained loyal to God, and were thrown down from heaven to hell. In their fallen state these angels of hell are supposed in Christian lore to be of hideous aspect, filthy, deformed and base.

Lucifer seeks to harass God by plaguing mankind with a multitude of troubles, and by inciting human beings to defy God. He uses his fallen angels as his agents, sending them abroad across the face of the world to incite and commit evil. Every time he succeeds in inducing a human to defy God, Lucifer gains another soldier in his rebellious army.

It is not always made clear how the demons of Lucifer can appear upon the earth when they have been cast down and bound in hell. Apparently, as we may gather from the Book of Job, Lucifer is able to walk upon the surface of the earth but is not permitted to directly injure human beings. He is even able to enter heaven!

It is written in the first chapter of Job that when the Sons of God, who are the good angels of heaven, present themselves before the Lord on some formal occasion, Lucifer gate-crashes the assembly. God asks him, "Whence commest thou?" Lucifer answers "From going to and fro in the earth, and from walking up and down in it."

God begins to boast to Lucifer about his servant Job, saying that there is no man like him, that he is a perfect and upright man. Lucifer cuts God off and asserts that Job is only a holy man because he enjoys God's blessings. He says he can make Job curse God to his face if God removes his protection. God takes the Devil up on this gentleman's wager, saying to Lucifer "Behold, all that he hath is in thy power; only upon himself put not forth thy hand." The events in the Book of Job are the result.

We may gather from this fable that Lucifer is not bound to hell exclusively, but is only bound not to injure those humans who are afforded the protection of God. A human being is protected by God for so long as he or she remains obedient. When a person defies the will and commandments of God, then he or she becomes prey for Lucifer.

Under ordinary circumstances Lucifer cannot directly hurt persons under God's protection, which is why he needed a special dispensation from God to injure Job's property and family. However, we are able to gather from other hints in the Bible and in Christian and Jewish folklore that Lucifer is free to suggest to human beings that they voluntarily defy God. Once a person does so, he or she forfeits the protection of God. Then Lucifer is permitted to commit injuries upon the person. What is true of Lucifer himself applies to his agents, the demons.

In a nutshell, this is the Christian demon myth. Demons are tempters of men because they are forbidden to injure human beings who obey God. But if through the temptation of a demon a person can be induced to disobey God, that person is demon fodder. Effectively, they join Lucifer's army of apostate fallen angels, although at a very subordinate rank.

From a Fundamentalist Christian point of view, all those who fail to worship Christ are disobedient to God, and therefore prey for the demons who walk and swim and fly upon the earth. Much the same belief concerning those of other religions is held by Fundamentalist Islamics and Jews.

In a broader inter-religious sense, anyone of any religion who strives to do good is afforded protection against the injuries of demons by God; but anyone who knowingly commits acts of evil loses that protection and becomes Beelzebub's chew-toy. This is more or less the modern view of demons held by those who believe that traditional demons actually exist.

We see this belief surfacing again and again in all sorts of folk forms. The Ouija board is thought by some to open a doorway to hell, allowing demons to possess those who unwittingly use the board. However, these unfortunate dabblers in the occult, who in films always seem to be teenagers guilty of drinking beer and necking in the back seat of cars, can save themselves from the talons of the demons if they burn the board and give themselves in the service of Christ through fervent prayers.

In Christian writings demons in the strictest sense -- those fallen angels who remained loyal to Lucifer in hell -- were continually being confused with pagan deities and with nature spirits. Thus we find mention of the demon Satyr who incites men and women to lust, and the demon Theutus, who induces the urge to gamble for money with cards or dice. The satyr is a nature spirit of Greek mythology, and Theutus is a degenerate variation on the name of the Egyptian god Thoth, who was associated by the Greeks with numbers, and by extension with money.

In the Dark Ages and Middle Ages, demons were thought able to travel on the earth invisibly, but to assume physical bodies at will. The same was understood concerning angels. This has a certain logic. In order to tempt human beings, demons need to remain invisible while they whisper seductive words or cause opportunities to commit sin to fall across the paths of their intended victims. But in order to murder their victims once their temptations succeed, demons need to have teeth and talons capable of ripping flesh.

The modern view of demons, among those who believe demons in the Christian sense to exist, is that demons are usually invisible but are capable of revealing their forms at their pleasure. It is not so widely accepted that demons can make their forms material. The modern demon is thought to punish those who give in to its temptations by possessing the victim's body and using it against the victim and the loved ones of the victim. Frequently the possessing demon causes the victim to commit a horrible crime, such as the mass murder of elementary school children, before committing suicide.

Some believe that the majority, and perhaps all, of the senseless crimes of violence, torture, perversion and hatred committed in the modern world can be attributed to the actions of possessing demons who have succeed in their efforts to tempt human beings to sins of evil, and having gained control over sinners by this means, are then free to use them as instruments to commit even greater works of evil. The karmic consequences for these greater crimes fall upon the soul of the damned human being possessed by the demon, not upon the demon itself.

In effect, once a person has acquiesced to the temptations whispered into his ear by an invisible demon that haunts his steps as he goes about his ordinary life, the demon is given a blank check by God to use that person to commit the most atrocious acts the demon can imagine.

Not all of those possessed by demons commit mass murder and kill themselves. More often they continue to live in spiritual torment and self-loathing, periodically committing little acts of spite and malice, while the demon that inhabits their body delights in their despair and hatred. According to this opinion, which seems to me to have considerable merit, the prisons are filled with those who have voluntarily given up control over their own souls and are hosts to demons.

The longer a demon holds residence within a person, the more difficult it is for that person to cast the demon out. Rituals of exorcise can aid an individual to expel a demon, but are only effective when the afflicted person sincerely wants to be helped.

A demon is expelled when its host simply refuses to obey its directives to commit criminal and hurtful actions. There is no advantage for a demon when a human being ignores its temptations, and ceases to surrender to its abuse and intimidations. The demon leaves.

The notion that the name of Jesus in itself has power over demons was disproved by the Biblical incident of the Jewish exorcists who attempted to use the names of Jesus and the apostle Paul as magical words of power to cast out a possessing demon from a man. The demon said through the voice of its human host "Jesus I know, and Paul I know; but who are ye?" The demon then used its host body to beat the Jewish priests until they were compelled to flee for their lives.

This story is usually interpreted to mean that only a follower of Christ can cast out demons in his name, but it seems to me to indicate that a desire to be free from the demon is necessary on the part of the person possessed, and if this desire is absent, mere words and names are of little use. The Jewish priests were not offering the possessed man salvation for his soul, but were merely attempting to intimidate the demon into leaving.

Lists of demons occur in some of the darker grimoires, notable among them the Lemegeton or Lesser Key of Solomon. This is a collection of tracts about ritual evocation and spirit magic. The first tract is named The Goetia and consists of a descriptive list of the seventy-two demons which were bound by King Solomon with his magic seal ring in a vessel of brass or copper, and cast into a lake (or the sea -- accounts differ).

To modern eyes, medieval images of demons may appear comical and quaint. You should realize that these images, and the understanding that Christian demonologists had about them, were merely unsophisticated attempts to come to terms with real, perceived phenomena of daily life.

People suffer temptations, sometimes temptations of the most horrible and perverse nature, for no clear reason. They commit grotesque crimes of violence against animals, human beings, and even against themselves, with the foreknowledge that these acts are hurtful to their own self-interests. They sometimes become possessed by spiritual beings and lose the ability to control their words and actions, or even the awareness of what their bodies are doing.

Those who have committed unspeakable acts sometimes state that they felt themselves to be in a kind of trance, distantly aware of what they were doing, but unable to stop themselves. They say it was like watching the crime unfold on a television screen; as though it had been committed by someone else.

How many know persons who seem to have every advantage in life, yet who willfully and perversely set about destroying themselves through the use of drugs or alcohol, or by committing perverse and dangerous sexual acts, or by abusing their own bodies with unnecessary medical procedures, excessive dieting, over-eating or smoking? How many know persons who are unable to control their own anger or desires no matter how important it is to do so?

These unfortunate individuals seem to be driven to self-destructive actions by an evil will that is present within them, but is separate from their own will. Sometimes this self-destructive behavior is overt, as in the case of physical self-abuse and suicide attempts. Other times it takes the form of malicious or criminal actions directed outwardly against family, friends or strangers. Yet always its ultimate result is the destruction of the individual soul that voluntarily commits these actions.

If you dismiss the image of the medieval Christian demon arising from a hole in the ground with a puff of sulfurous smoke, do not make the error of assuming that you have also dismissed the reality that demon represents. Rather than assert that demons are unreal because your own preconception of them seems ridiculous, at least consider the possibility of changing your concept of what a demon is.

Demons in one form or another have been a constant fixture of folklore and myth in all cultures around the world since the dawn of history. While this is not proof that these folk beliefs are literally true, it suggests that a core of truth exists that has sustained and defined the myths of demons over the centuries. It is nothing short of intellectual arrogance to leave unexamined so universal an aspect of human experience.