Granted, the most recent edition came out in 1974, but Words Into Type is still the reference I turn to first with grammar and usage questions. (For style, I keep the NY Times Manual of Style and Usage handy.) Unlike the Chicago Manual of Style, WIT has a usable index that must have been put together by a mind-reader. It's organized the way people think and usually anticipates the form my bewilderment will take: Does "what" take a plural or singular verb? The answer's under "what" in the index. Should I say "as if it was" or "as if it were"? Look under "If clauses." Is it different from or different than? The index leads me right to my answer. I wish the editors would come out with a new edition, but for now I'm loyal to the increasingly ancient Third.