It's called "How to Draw Monsters" by Larry Evans and published by Troubador Press. He also did one on Prehistoric Monsters. If I find the actual book I will post the cover at least.
I thought the publisher was "Paladin Press", but they publish White Suprmacist and Compound dwelling books on guns, how to be a terrorist...
Troubador put out some great coloring books and I remembered I owned a few. On the back page, they list all their products and the Larry Evans drawing book was on one of them.