Grammar-book advice

[Jesse Sheidlower]

A co-worker wants to buy a grammar of American English. She's
interested in some more or less traditional thing that discusses the
usual array of morphology, syntax, and stylistic features like
punctuation.  She does not want something highly theoretical, nor does
she want the sort of superficial Avoid These Errors book. Just
something reasonably thorough and usable by an intelligent
non-linguist.

Does anyone have a suggestion? When I used grammars they tend to
be either Quirk et al. or the seven-volume Jespersen, and I don't
know what to advise for this purpose.

Thanks.

Jesse Sheidlower
OED