Is the nature of human populations consistent with monotheism? Just as the world of natural phenomena is complex and varied, so is the array of nations and tribes that make up the human race. The way of Asia is not the way of Africa, which is not the way of Europe - is it logical that one Supernatural Power can be the only true God for all of mankind? Is it not more reasonable to assume (as in fact each tribe and nation insisted until convinced otherwise by fire and sword) that each group has a set of Gods that expresses divinity in accordance with its own vision?
Does the direct spiritual experience of mankind, as witnessed by shamans, mystics, and holy men, support the contentions of monotheism? On the contrary, countless cultures assert that the multiverse is teeming with non-human entities, many of which can be categorized as Gods and Goddesses both major and minor. The claim that there is only one God is by no means the only view. Indeed, the existence of Thor, Odin, and the other Norse Gods was acknowledged by Christian missionaries and chroniclers, while the idea that they are fictional is a more recent development. Of course, the position of the Church was that the old Gods and Goddesses were demons - but the self-serving nature of this claim makes it transparent to all but terrorized peasants.
In summary, monotheism is contradicted by our observation of nature's manifold and differing phenomena, by the widely diverse peoples that make up humanity, by the direct experience of those in every culture who deal with the Otherworld, and even by the testimony of men who claim to follow the One God!
Books in PDF format to read:Solomonic Grimoires - The Emerald Tablets Of Hermes
Anonymous - The Emerald Tablet Of Hermes
Medieval Grimoires - The Grimoire Of Honorius