From the Hero Games website:
No matter what genre you choose or setting you use for your HERO System campaign, one constant is Skills. Virtually every character, from the most powerful superhero to the weakest peasant, has at least a few Skills, and some characters depend on them every adventure to get things done and keep themselves alive.
The Ultimate Skill is your guide to Skills in the HERO System, with advanced, expanded, and optional rules covering every aspect of Skills and Skill use. It includes:
—expanded rules for buying Skills, including altering their costs and purchasing lots of them easily
—advanced rules for Skill modifiers covering every genre and setting
—expanded rules covering everything about Skills including rules for learning Skills, Skill Versus Skill Contests, degrees of success and failure, Complementary Skills, extended tasks, team Skill use, and much more
—detailed descriptions of every Skill in the HERO System rules including common uses, historical information, appropriate modifiers, equipment used, time required, expanding or altering the Skill to suit different types of campaigns, and genre-by-genre applications
—optional new Skills
Whatever game or type of campaign you play, The Ultimate Skill is filled with information to make it and your characters better and more exciting!