Call of Cthulhu: Letters from Arkham
English by William H. Pendergast I, 1800s
This small, handwritten black book looks innocent enough. Seemingly a book of mathematical techniques that is far ahead of his time, but has much more to it than that. It speaks in oblique terms of how space and time might be bent and folded like paper, and contains veiled allegorical references to Daoloth. Requires a Physics or Mathematics roll to understand, in addition to any Other Language rolls required.