I noticed that a third edition of Garner’s Modern American Usage has been published. I’ll be purchasing a copy, as GMAU has been the first thing I turn to when looking for guidance on general English usage.
Would GMAU be of any use to contract drafters? The language of contracts is limited and stylized—it’s analogous to computer code. But once you’ve mastered the core usages, there’s plenty of room left for flair in determining the clearest way to articulate a concept. So a command of general English usages would come in handy for purposes of drafting contracts, and a good reference work would come in handy for purposes of developing your command of general English usages.