Take a look:

Full of hilarious information about the English language that even the gurus will find fascinating. In the words of Brian Gongul, this is "a coffee table book for the brain."

This should be the any editor's permanent companion. I also highly recommend it for when you're self-editing. Learn how good story-telling works, why it works and—most importantly—learn how to produce the most professional manuscript possible.  

Join Shawn Coyne, author of Story Grid and a top editor for over 25 years, and Tim Grahl, struggling writer, as they discuss the ins and outs of what makes a story great. A must-listen 

companion to the book.

American (US) English. Invaluable if you're self-editing, this is the quintessential reference work for authors, editors, proofreaders, indexers, copywriters, designers, and publishers. I recommend you consider buying an online subscription. It's a little more expensive, but much easier to navigate.

Now in its 17th edition, The Chicago Manual of Style Online is a mandatory reference work with more than two thousand hyperlinked paragraphs. I feel the annual subscription is worth while, even though it's slightly more expensive, because it's quicker and easier to navigate than the print version.

Available in print and ebook, Merriam-Webster's Collegiate Dictionary is the preferred dictionary of The Chicago Manual of Style. It is now in its 11th edition.