Two main attributes---its organization and its completeness---make this reference so valuable. For example, chapter 5, a treatise on the pleasure and pain of punctuation, starts with the various forms of terminal punctuation before moving into a substantial discussion on the comma (there are more than 20 subpoints discussed on the uses of the comma) and concluding with a roundup of the remaining commonly used marks of punctuation. It's easy to find out the distinction between, say an en-dash and an em-dash, or get a definitive answer about why we need to include serial commas (despite the outdated advice offered by the badly out-of-step AP Style Manual).
The advice about names and terms found in chapter 7 seems daunting at first, but the presentation is, again, so well-organized and complete, that, after some study, you will start catching all the errors that make their way into too much printed material these days. The advice here about when to capitalize words such as "federal," "government," or "state" trumps the misleading, confusing dictums of other outmoded texts such as the United States Government Printing Office Style Manual.
One more example of why the Chicago Manual of Style is a beacon of calm authority can be found in the common sense approach to the difficult issue of being consistent in the use of numbers. Nothing drives me crazier than fighting with a manager, copy editor, or researcher about the use of numbers. Here the emphasis is on laying on the general principles not as absolute rules but as guidelines followed by a generous overview about the myriad exception and variations to these principles. Numerous examples cover virtually all the situations one might encounter.
Any new copy editor worth his or her salt will have highlighted practically the whole second chapter on copyediting; veterans will return here frequently, too. Both will likely have, at some point, thumb tacked or taped a photocopy of Figure 3.1 Proofreaders' Marks within easy viewing distance.
Detailed discussions about references and bibliographies, indexing, marking manuscripts, and copyright law (though this is one place where the book is beginning to show its age, for the impact of the Internet on copyright matters was not foreseen when this book was published) round out this reference. Sections on foreign languages, scientific terms, and mathematics in type illustrate further why this book anchors the writer-editor's reference collection.
I eagerly wait for the 15th edition to be published.
My only problem with this volume is accessibility. It's not always easy to find the section dealing with a particular problem. For example, you may have to wade through several pages before you can determine which version of a citation is correct for your situation. Despite this difficulty, I cannot deduct a star from my rating since no other book compares in scope and accuracy when it comes to the mechanics of writing.
I highly recommend this book for anyone who writes articles, technical papers, or books as part of his or her profession. College students should consider buying it as a reference tool that will never steer them wrong.
The usefulness of two specific areas that demanded my attention were met with thoroughness and clarity in this reference: copyright permissions and endnotes. Every single scenario was covered minutely, and provided the style assistance I needed.
My only comment to you authors/editors is not wait as long as I did to purchase. Get the hardbound, you'll likely wear the softcover out quickly. This is complete deal for style.