"It is true that there is a lot of information in the libraries of today, but as I understand it, those writings are mostly conjecture derived from bits of physical evidence from construction methods that have been "supposed" to exist during the time period of their construction"

You understand wrong. The evidence for and of construction techniques and the location of the quarrys is about as decisive as you can get.

"here still seems to be some discrepancy as to "when" the pyramids were constructed. Some authors state that they were build about 4,000 years ago but some say that there is evidence that they were constructed earlier, or about 10,000 years ago.
"

Oh, really? Care to share this evidence? I know about which two cranks you are talking about, and their supposed 'evidence' is absurd- in fact it does not even rise to the level of your characterization of the evidence you disagree with. Be careful, look down- its called rhetorical thin ice.

"It is said that long ago there used to be a great library in Alexandria, that contained among its 700,000 volumes of writings, information that dated back to the time when the pyramids were build. What a shame that such information does not exist anymore.
"

700,000 is dubious, but in the absence of evidence any speculation is as good as another. The absence of that data neither affirms your assertions regarding the age of the megalithic structures of Egypt, nor denies the existing evidence regarding their age.

"I know that it is hard to imagine that someone four thousand years ago could have been smarter in some ways than you are today but such might have been the case."

Its quite easy to imagine, Johannes.

"I have read somewhere that there are old Sanskrit writings about how the stones of the pyramids were moved to the construction site, they do not tell of long ropes and thousands of slaves, but you would not believe such stories because it would involve the understanding of such phenomenon as transverse and longitudinal vibrations in synchronized resonance within the material being moved. "

Okay. Right. Whatever. Why don't you post those learned sources here for us to laugh a.... I mean inspect...

Davin L.