I inherited a copy of The Gregg Reference Manual, Tenth Edition from my friend Carina last year. I don't use it too often, but it has served its purpose a few times. Most recently, my hubby was reading one of our local entertainment rags and thought he found a typo in one of the ads. Knowing how I live for that kind of thing, he pointed it out to me, asking, "Should this be 'capitol' or 'capital'?" (to put it in context for you, the ad mentioned something about "the capitol city")
I was fairly sure I knew the answer ("capital"), but just to be sure I hauled out good ol' Gregg. Within seconds, thanks to the easily-navigable index, I found the entry I was looking for: capital-capitol-Capitol, and the answer was at my fingertips in a jiffy. The ad should have read "capital city," as "capitol" refers to a building, not a city.
I have used several other style manuals, some of which have been quite difficult to use. Others simply have not had enough detail to answer my questions. But so far, Gregg hasn't disappointed.
So . . . anybody want to share their favorite style manual or reference book?