Vintage Beer: Discover Specialty Beers That Improve with Age - Patrick Dawson
A great book for lovers of quality beer and its complexities.  The book also provided some very good and easily digestible information on evaluating and defining beer flavors and composition.
 
As someone who brews and who enjoys craft beer I found this book interesting.  It does change how I think about some things.  I never thought to deeply about aging beer or its freshness.  Generally 'aged' beers are marked as a feature of specialty craft beers, regardless of if they actually taste good.  Cheap beer I'm generally not buying for it's taste.  Now I understand a bit more why sometimes 'aged' is not always better.  This is a nice addition to my knowledge base.
Source: http://libromancersapprentice.blogspot.com/2013/11/book-review-vintage-beer.html