The Oxford Dictionary for Writers and Editors is a fabulous source of information for anyone who works with words.

The book covers just about every aspect of writing and editing; including all the standard symbols used for proof-reading, transliteration, a full guide to accents, and guidance on a wide range of topics, such as the foreign language phrases that we use every day. It also covers common spelling difficulties, and hyphenation and punctuation etc... Basically, everything you could possibly need if you are a writer/editor by profession or for pleasure.