Woe Is I: The Grammarphobe's Guide to Better English in Plain English, Patricia T. O'Conner,
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ISBN 1573226254
Informative, funny, a great book about the mechanics of writing. Her coverage of punctuation should be required reading for all would-be book authors. Fairly inexpensive, even (eleven dollars US, list). Highly recommended.
I haven't read her other book, Words Fail Me, ISBN 0156010879; anyone? -- Paul Chisholm
See original on c2.com 