Based on the fantasy Lost Worlds game books (but incompatible with the Lost Worlds series). Each player uses a book and a stat sheet that represent their 'mech. By giving your opponent your book, and taking theirs, you get to see the actual first person view in the combat.
Books in the series include:
GRF-1N Griffin
LCT-1S Locust
RFL-3N Rifleman
SHD-2H Shadow Hawk
WHM-6R Warhammer
WSP-1A Wasp