[The following are excerpts from handwritten notes discovered secreted in a hidden alcove in the west wing of the Phillips-Ervin Museum, London England.
Sealed in a leather canister, the aged script was accompanied by an ornate bronze key of unknown origin.
The author of the journal remains unidentified, and the artifact was only chanced upon following the museum's partial destruction during the spring of 1941...]

[Fragmentary entry I:]
I have come into possession of a certain ancient book, a collection of arcane scrawlings reputed to have been derived from an even earlier transcription, allegedly lost during the great fire of 1666.
The Chthonic Chronicles!
I cannot disclose here the precise and rather unsavory means by which I acquired this weather-worn tome, but I immediately recognized the veracity of the fevered inscriptions contained within.
Apparently derived from an incomplete Latin translation of the original source material, the text sporadically lapses into an indecipherable tongue which the translation cryptically notes as being Old High Atlantean.
Glyphs, sigils, occult pictograms, six score and ten oblations to some malign entity of colossal evil... some diabolical avatar of the Z'xulth.
Khthon!
I must delve further into the foreboding depths of this great black book...

[Fragmentary Entry II:]
Caught in the maleficent whorls and verticals of this dark tome... but what lies at the heart of it?
A vespertine viper's nest of sublime wickedness!
What I discovered within this shadow-haunted volume was a terrifying axiom so inestimably terrible in its magnitude that it would shatter all man's carefully orchestrated views of the cosmos and render utterly redundant previous theories on the origin of humankind.
Lore dating from time immemorial