Luigi Serafini's 1981 illustrated encyclopedia written in an indecipherable invented script. Italian surrealism at its most committed.
From Wikipedia
The Codex Seraphinianus is an illustrated encyclopedia of an imaginary world, created by Italian artist, architect and industrial designer Luigi Serafini between 1976 and 1978 and first published in 1981. It has approximately 360 pages and is written in an imaginary writing system.