From the back of the book:
"Don't be 'Strong Caveman', be 'Impressively Strong Caveman'. Don't be 'Grunting Caveman', be 'Oooh Grunting Caveman'. This supplement expands the 'Land of Og' by providing specialty caveman kits, source material on caveman interaction, a sample adventure and caveman life in the bid cities. Don't leave your cave without it!"
The book has some cartoon-like illustrations and provides advantages and disadvantages to playing certain types of cavemen.