There are so many different themes - yet all with a common thread that it is difficult to select a starting point; and also difficult not to wander off the point. We might as well begin with begin with Ancient Egypt.
Many records were lost when the library at Alexandria was destroyed; a common happening in the past, including deliberate destruction of records and histories in China and other lands; yet we have some information from Greeks who travelled to Egypt. Among their legacies to us is the Atlantis legend, for example. Whether we think Atlantis is a fairy-tale, it is clear that the Egyptians had records of floods other than The Flood, of great cataclysms that caused East and West to change places and of civilisations still unknown to us. The. question is not "was Atlantis a real civilisation?" but "what other civilisations were there - and how many?" How far back do Man's civilisations go?
Intermingled with all this are the legends of a Golden Age, when Man was innocent, the world was perfect, lacked confrontation, cruelty, pollution... Is there any truth in the legend, or is it all the wishful thinking of Men who would like to be as perfect as the legends suggest, but, being flawed, cannot? There is no reason to suppose that Man will not eventually rise out of his present state and become something better; but so far Man has had a good 5,000 years or more of 'civilisation' without improving much on what he was at the beginning.
Where did Man come from? There are those, like von Däniken, who would have us believe that Man was genetically engineered from native anthropoid stock by space travellers (the Gods of the Legends, who taught Man); this might explain why Man is flawed - perhaps the genetic engineering wasn't done properly; the legends suggest, on this theme, that the space travellers had several tries - and then wiped out their mistakes. Isis and Osiris, Thoth - all teachers of Man - they could well have been visitors from space; they might have engineered Man.
Such legends of Man being taught by superior beings make me think of stories of primitive tribes being contacted and educated by representatives of a more advanced and civilised people not necessarily from another world, but from another part of our world. In our own age we can contrast the advanced Western computerised streamlined tidy world with the tribes of the desert, poorly educated, scratching a living, helped, sometimes hindered, by the techniques, technology and ideology of the West.
Whether Man came from the stars, was created by God, engineered by visitors or evolved from anthropoid stock is irrelevant. We can assume, looking at the rise of modern civilisations, that once Man was established he went through various stages of development until he created a civilisation that we would recognise as such. Having achieved this, and like us, using technological advances to improve his lot, he reached a stage similar to ours; comfort, leisure, cleanliness, time to think and speculate, investigate and learn. Knowledge would be assembled, stored - as we do with our computers - and broadcast throughout the world.
We assume a lot; that we are the first to have horseless carriages, to fly, to explore space, to develop computers - and yet there are legends that suggest the opposite: that we are in fact not the discoverers of all these things, but the re-discoverers. Just for thought - why could the Oracle at Delphi, churning out enigmatic messages on leaves, not have been a computer spewing out sheets of paper, uninterpretable results of some program long forgotten? Possible, if its constructors and users were no longer there, and ordinary, less educated folk came across it? Was the "Brazen Head" perhaps a form of robot? or a computer console that could talk and understand speech? Have we perhaps already been through all this before, and our wars, our atomic missiles, our technology and computers - are they but shadows of what has already been, and will eventually come again, even if we are wiped out? What memory of computer time-units perhaps caused the Indians to divide their day by 60 and 60 again down to tiny units that would have been of no practical use to noncomputerised man?
Von Däniken and others have made great play of aircraft-like artifacts found in South America, and of the Indian legends of vimanas (flying machines), weapons of enormous power that are likened to our atomic-headed rockets and bombs; and it is hard to explain away the similarities in these same legends to the results of modern atomic warfare.
Did people just make up the legends? Are they just fairy-tales or memories of some half-forgotten holocaust, a time of such destruction and terror as to cloud and confuse the memory? Had there been such wars then it is likely all those who understood the weapons and vehicles would have been destroyed. Do you understand how your television set works? You just watch it. And if for some reason we were to lose electricity so that there was no television any more, would television itself not become a legend? Moving pictures; a voice in a box; a talking box; a mirror to see people in faraway places...
Those who champion the spaceman theme also paint to evidence of civilised people in uncivilised regions - flints shaped into tools, rock paintings of advanced technique, for example, suggesting that these are examples of what would be produced by the crew of a spaceship that crashlanded on Earth. Possible; but equally possible they could have been the survivors of a war, or some natural cataclysm.
It has been suggested by many, in particular Velikovsky, that there was at least one great cataclysm that wiped out people and creatures and civilisation. An asteroid strike is the most favoured nowadays. Memories of what went before would become legends; records of knowledge would be lost, and become tales for the long evenings. And yet you would think there would be some trace of memories of civilisations before such a cataclysm that could be retrieved; hypnotists have been successful in "regressing" people to what they believe is one of their past lives on Earth. Yet no-one seems to have been able to return to a life in the past earlier than one in Ancient Egypt. Is there a mental block that does not allow us to go beyond the cataclysm - the waters of Lethe? It depends rather a lot on whether regression is what it makes itself out to be. For all we know people who are regressed might be tapping into a race-memory shared by everyone and locked away in the 90% of the brain we don"t apparently use; it could be one of their own past lives; it could be the brain's ability to create a life out of the knowledge acquired and stored by the individual. Take your choice: no-one has gone back beyond Egypt.
This in itself proves nothing; we can but speculate on the past and the history of Earth, but there seems no way we can discover the truth about Man's origins and the history of the Earth.
Recently there has been more speculation about Atlantis; Berlitz says it is in the Atlantic; Edgar Cayce predicted it would be discovered soon and there is evidence of man-made streets under the sea where Atlantis may have been. There is no reason why there should not have been an island in the Atlantic; it would have blocked the Gulf Stream, thereby making Europe rather cold, as history suggests it was. Those who theorise about Atlantis suggest that it was destroyed, and that the survivors made their way to other countries, bringing civilisation with them, educating Egypt, building the pyramids; and so on.
What history and legend we have from Plato suggests that the Atlanteans were empire-builders, imperialists - perhaps highly civilised, with a culture, but not necessarily the ideal type of Man, and certainly not the inhabitants or creators of any Golden Age. If Atlantis is ever excavated (or dried out, considering where it is) the archaeologists will find neither the Garden of Eden, nor a Golden Age; Atlantis will appear as but the remnants of a yet higher culture, and no better than Rome, or New York, simply an older version of so many cheap little mercenary-minded worlds, where the ruling clique is selfish, not altruistic.
Was Man ever as depicted in legends, innocent in Eden, blessed in Golden Age? Did he fall? Or has he carried the seeds of his own destruction in himself throughout his history, creating and destroying civilisation after civilisation, rising, falling, and then starting all over again, dragging himself up through Dark Ages to discover light? If so, can he ever reach perfection? Or, if he was perfect in the beginning, did the asteroid strike and radiation corrupt his genes?
If Velikovsky and others are only partly right, there have been several major cataclysms in the history of the Earth. The Flood alone suggests tidal waves of unimaginable force; Egyptian legends of the Earth rotating the opposite way to now; the record of magnetism in the rocks; the masses of creatures swept from different regions of the Earth and smashed into a common grave; the mountains pushed up suddenly (in geological time); the rising and falling of areas of land, some cities ending on mountains, others drowning; mammoths abruptly deep-frozen; - all this suggests immense and immeasurable forces, destroying flora, fauna and civilisations.
As for the causes of the cataclysms - wandering planets, meteors, comets, the Earth toppling over - these I leave to the theorists. I think there must have been cataclysms, both natural and man-made, cataclysms that may have activated genes in our DNA chain producing mutations with some features dormant until that point.Some scientists now suggest that types do not necessarily evolve slowly but can suddenly appear, as if by spontaneous generation
Is the glass half-full - or half-empty? Sudden mutations, and mutations adapting to a changed world could well be beneficial - and might even lead to a better type of Man, altruistic and thoughtful, an advance on the primitives, the self-centred, the non-thinkers of the world.
Or will history repeat itself, and some cataclysm plunge Man back into a new Dark Age, having to re-create a civilisation, rediscover what we have forgotten and rebuild the stores of knowledge it has taken us 2000 years to collect, and some previous civilisations, not known to us, perhaps even longer.
We may speculate; and the trouble with speculation is that we all end up like Adamski, Berlitz and Von Däniken - plenty of ideas and speculations, but few facts, and not a scrap of proof.
We just don't know. Perhaps we shall yet excavate proof somewhere that there were indeed civilisations prior to those for whom we have documentation and artifacts.