From the publisher's website:
Spell Law: of Essence probes the realms of the living force that binds and surrounds all living things-the magic of the universe is all around us. Tap into the natural Essence and shape your destiny!
Inside ...Of Essence you will find over 50 spell lists with hundreds of spells. Plus all of the character information needed to expand the core Essence professions of your Rolemaster Fantasy Role Playing game, including the Illusionist, the Sorcerer, the Mystic, the Monk, and other mind-over-matter adepts! Attack tables and critical strike tables give results for all kinds of magical attacks. And summary tables make all of the details easy to manage!
Now when the sorcerer raises his hand, you know that the world is about to crumble at your feet...