Skip Williams is one of the many writers of Dungeons & Dragons 3rd Edition alongside Monte Cook and Bruce Cordell. He is notable for his "Sage Advice" column that was run on Wizards of the Coast's website for a time, which covered errata, rules issues, and similar issues of Skubbery. Many of his clarifications were interesting, if only on a basic level. He also wrote several splatbooks for the system, which run the gamut from entertaining to absolutely game-breaking.
He is better known, however, for his creative interpretation of the rules and for absolutely fucking hating the semi-newly-introduced Sorcerer class. He is on record as repeatedly voicing his feelings that the Sorcerer "wasn't a proper caster class" and that in breaking with the Vancian casting system for a more spontaneous spells-per-day model, the Sorcerer was horning in on the Wizard's gig. According to several affiliated with WotC, Skip is the primary reason the Sorcerer is so much weaker than the Wizard, with slower spell progression, a general incapacity to take advantage of metamagic feats, and a huge amount of content that blatantly favors the Wizard over the Sorcerer - to the point where almost any book he wrote would openly shaft the Sorcerer in favor of the Wizard. Some of this fuckery was rolled back in 3.5 and Pathfinder, but a lot remains, such as the Metamagic restrictions and the Sorcerer's complete lack of Charisma-related skills, which is a real petty blow considering Charisma is the sorcerer's casting stat.
The Wizard/Sorcerer splatbook from 3.0, Tome and Blood, is one of the most notorious examples, as of the various prestige classes and items in the splatbook, a huge number of them blatantly favor the Wizard, such as Metamagic rods (which give Wizards free access to a Metamagic feat but mandates that the Sorcerer still spend a full-round action to use them). Of the fifteen prestige classes in the book, all but nine are vastly easier for a Wizard to acquire than a Sorcerer, and one is essentially Wizard exclusive. To elaborate: many of these prestige classes can be spliced into by level 6 for most, but a Sorcerer would have to be at least level 12 for the exact same classes. The one Prestige Class in the splatbook that is Sorcerer-exclusive also happens to substantially undercut the Sorcerer's spellcasting capabilities; it does not get any additional Spellcaster levels and essentially gains stats better for a combat-capable class.