Elijah Sithen? You mean Zecariah Sitchin? His entire corpus of work is rubbish.
Sorry, I miss typed--Yes I mean Zacariah.
But will all due respect, your view of his work is a little broader scope than fair.
The idea of "translating" all these hieroglyphics is misleading in the first place. He is demonstrably wrong on a number of important detail points (the 3500 year period being one of them).
But, that said, the planet has been visited on a regular basis over hundreds of thousands of years and maybe longer. The fundamental thesis of a specific group being the most recent is probably acceptable although they were not the only EBE's (Extraterrestrial Biological Entities) present at any given point in time.
The additional planet analysis seems to stand up--if more informed analysis turns out to be correct, we should see some real signs in the next thirty or forty years.
As a fundamental Christian, I have no difficulty in believing that God created a bunch of other huminoids in many different places; I see Jesus Christ as fairly separate from the EBE visitors--the historic record of who the players were and what the motivations of the actions were is confused. But Christ was real; and His message as enunciated in the Sermon on the Mount is God's description of righteous non sinful conduct.