elements, and brand new mechanics to account for them." Reviews Casus Belli #40 (Oct 1987) Legacy The monster on the cover art for the original Manual of the Planes, the astral dreadnought, was the inspiration for the Cacodemon in the DOOM video game series. References Bibliography External links Rpg.net review (3rd edition) Rpg.net review (4th edition) 1987 books 2001 books 2008 books Dungeons & Dragons sourcebooks ENnies winners Handbooks and manuals Role-playing game supplements introduced in 1987