Weird Fact anybody?

Maybe half what I read is actually non-fiction - which set me wondering: what is the strangest work of non-fiction (or putative non-fiction) ever published? I know about the Voynich Manuscript and Codex Seraphinianus, I mean the strangest intelligible work.

Well, Zen and the Art of Motorcycle Maintenance has to be right up there. I'm just finishing up my second reading of it.

My first thought was Thomas Browne's The Garden of Cyrus. http://en.wikipedia.org/wiki/The_Garden_of_Cyrus