Reading Usable Help
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Gordon R. Meyer
Usable Help Bookshelf: Quick & Dirty Tips for Better Writing
A new reference book, and the latest addition to the list of Favorite Books in the sidebar, is Grammar Girl's Quick and Dirty Tips for Better Writing. It's a handy and casual reference for the conundrums of daily writing. You'll find entertaining and accurate answers to common grammar questions, and some good mnemonics to help you remember the answers later. While it won't replace a professional style guide (and isn't intended to) I think most writers will find it useful and fun.