Who Was Melchizedek
I would rather think that Melchizedek was Christ, before he was Jesus Christ in the flesh. Abraham knew of him. I would rather say Enoch had direct access to heaven, God and many mysteries.
These mysteries may have been very well passed down to Abram. Now whether he had any contact prior to this event, no one really knows. Melchizedek, however, had no beginning and no end, thus this would lead me to the conclusion that this was the son of God before the crucifixion, preincarnate, since jChrist was, and is, God incarnate in human form.
Apparnetly Salem was a place that all the sons of God and their descendants knew of. Salem was a holy place of great respect or possibly even fear. Salem very well may have been the Garden of Eden itself.
It was protected by the cheribum; and no one except God could pass. Since Christ is in fact God in human form, He may have been the only one able to pass.
Even the sons of God, and even Satan, had great respect and fear of Melchizedek.
In summary, this particular person was well known throughout the world, even in these days of old. Gods plan for mankind was being established. Even in some of the writings of old Egypt there was mention of Melchizedek. It has been suggested that the pyramid of giza and the original sphynx predate Egypt by at least 1500 years, and may have been constructed by Melchizedek himself.