This preface, clearly written at some point much closer to the encyclopaedia’s conclusion than its first entry, frames the unknown author’s experiences of the impossible.
A General Sense of Unreality, or; A Unified Theory of the Impossible (A Preface)
With enough cunning and the right tools, the distinction between possible and impossible is a more permeable and more malleable boundary than most perspectives allow for.
There are many horrors that can freeze the blood of their victims by turning their gaze upon them. Fewer can paralyse someone with the merest knowledge of their presence.