Some of the comments above are bordering on the absurd.
There is no good theory of how the Moon was formed, as they all have major problems that are insurmountable. For those who are interested in the mainstream’s best guesses (which is exactly what they are) please see below:
https://www.sidmartinbio.org/what-is-the-best-explanation-of-how-the-moon-came-into-existence/
The supposed ‘prevailing’ theory is also known as the ‘Big Whack’ hypothesis (although personally I think to call this idea a ‘hypothesis’ is stretching the word beyond breaking point) and it’s biggest problem is the Angular Momentum is all wrong, along with the near circular, tidally locked orbit - so much so that recently a second impact had to be hypothesised in order to create the orbit we now see. The odds against that are literally astronomical. Far too often these days we are seeing impacts being given as the only ‘explanation’ and it seems to me that lazy so-called ‘experts’ have been allowed to get away with that tired ‘explanation’ so often it is now the first one they go to.
We are supposed to believe a Mars sized object just happened to hit at just the right speed & angle to knock a great chunk off the Earth, and at just the right moment a second impactor - coming in the opposite direction - just happened to also hit at just the right speed & angle to impart the required angular momentum and additionally magically correct the trajectory of the supposed chunk knocked off the Earth to put the new body - The Moon - into it’s current tidally locked orbit? Yeah. Sure. I’m convinced. NOT!
https://forum.cosmoquest.org/forum/science-and-space/space-astronomy-questions-and-answers/60585-?66926-Moon-Impactor-Theory-(The-Big-Whack)
https://setiathome.berkeley.edu/forum_thread.php?id=33405
The ‘Big Whack’ is simply a guess - it is neither an actual theory (you will notice if you read through some of the referenced threads that modelling the ‘Big Whack’ does not work so it is immediately discredited as a ‘thought experiment with computer graphics’ when modelling is accepted as better than observations when the Mainstream see it coming down on the side they are promoting. You cannot have this both ways - the same people who say that the modelling done that shows the Big Whack is flawed beyond salvation and ‘thought experiments with computer graphics’ - really? See https://forum.cosmoquest.org/forum/science-and-space/space-astronomy-questions-and-answers/60585-?p=1663172#post1663172 and read the thread. Again, I say to you all ‘Angular Momentum’ - it is all wrong and totally eliminates the ‘Big Whack’ theory.
Finally why has everyone focussed on the one loony idea in the book - Time Travellers? It is almost as if that was added simply in order for the book to be easily discredited, but why? The book talks about things that are provable and moreover easily demonstrable as well. The Megalithic Yard is real - and seems to have been in use back in the Neolithic period as well as being the origin of both the Imperial system of measurement as well as the Metric inasmuch as both are based on Planetary Geometry. This smacks of a taught system. Every ancient civilization tells you they were taught - the Egyptians, the Sumerians, the Aztec, the Inca - all TAUGHT their at the time seriously advanced knowledge.
Not by aliens either (although they certainly exist) but by the shattered remnants of the Global civilization that was wiped out 12,000 years ago.