Reccomendation for word 2013 book

What you should read really depends on what aspects of Word you're interested in. A book that tries to cover everything is unlikely to go into the same level of detail as a specialist book. One area most Word books fall down on, for example, is with Word field coding. Few go beyond the most basic aspects - the on-line tutorials I've published have far more detail than any book you'll buy. See, for example, my:
• Microsoft Word Date Calculation Tutorial, at:
http://windowssecrets.com/forums/sho...ation-Tutorial
or:
http://www.gmayor.com/downloads.htm#Third_party

• Microsoft Word Field Maths Tutorial, at:
http://windowssecrets.com/forums/sho...Maths-Tutorial
or:
http://www.gmayor.com/downloads.htm#Third_party

• Microsoft Word Catalogue/Directory Mailmerge Tutorial at:
http://windowssecrets.com/forums/sho...merge-Tutorial
or:
http://www.gmayor.com/Zips/Catalogue%20Mailmerge.zip

• Microsoft Word Mailmerge Tips & Tricks, at:
http://windowssecrets.com/forums/sho...ips-amp-Tricks
or:
http://www.msofficeforums.com/mail-m...ps-tricks.html

A book you might find useful is The Secret Life of Word: A Professional Writer's Guide to Microsoft Word Automation, by R Delwood, published by XML Press in 2011(http://xmlpress.net/publications/word-secrets/). I contributed content for and did much of the technical review of this book. This isn't a programming book as such (though it does have some programming in it) and doesn't profess to teach you how to program. Rather, it shows how to combine Word's various tools to achieve whatever the desired result might be. And, although it predates Office 2013, everything it in would be relevant to Office 2013 as well - most, if not all, would also apply to Word 2007.