Please note: Because of yet another new program I was able to complete this in minutes, rather than days.
Note also to Alan Walton: If you should see this page, I am not attempting to rip off your material and I give you full credit for it- I offer it here in such a form as to ensure ease of use.
Perhaps a few words about this text are in order since it's only peripherally related to the sort of occult and metaphysical content I have been uploading:
This staggeringly large collection (over 500 pages) of primary and secondary source mentions of the hollow earth theory, replete with tales of UFOs, cryptids, and mentions of both contemporary and historical (sometimes ancient) reports of encounters with "the little people" or extra terrestrials in caves, mines, mountains, glacial areas, deserts, and so forth, I first encountered back in 2007 while researching cryptids, when I stumbled upon a site hosted on angelfire and run by a man named Alan Walton (the site link will be listed at the end of this post- but I have tried to contact its owner and believe the site to be essentially abandoned.) Thankfully, as the files used to compile the pdf were fairly small word documents, the overall size of this over-500 page document is smaller than even a single high quality scan from my own collection, and thus is available as one very small download.
The document itself is mainly a collection of reports and legends dealing with the subject matter- primarily tunnels or caves leading to locales of an extra terrestrial, inter-dimensional, or metaphysical nature- but it also heavily covers UFO bases, USOs, government conspiracies, secret societies, Native legends from at least three continents, cryptobotany and cryptozoology, metaphysics, the occult, various religions, and anthropology/ archaeology.
While I do not myself believe the Earth to be hollow, per se, it is something which is "technically" possible and, due to the very limited exploration at the northern pole and of very large cave systems, could theoretically exist without our knowledge- some physics experts have indeed even in the modern era discussed the faint but feasible notion that our planet has at the very least hollow pockets. Even if you discount this as myth, it is indeed true that the structure of the crust almost surely contains caves, caverns, even possibly small oceans which we are not aware of, or only dimly so.
Like Brantonia's site itself, this text is best looked at as a great compendium of material on the more cryptic or metaphysical, replete with decades of obviously painstaking research collecting, and is sure to find many fans.