Let’s start with the basics. The Beer Bible by Jeff Allworth is a comprehensive and essential book arranged by types of beers and includes beer histories and information on how each is made. So You Want to be a Beer Expert by Jeff Evans (are all beer experts named Jeff?) will enable informed conversation about the merits of various types of beers.
If you are a foodie who likes to entertain and to cook with brews, then check out Stephen Beaumont’s The Beer and Food Companion and Mark Dredge’s Cooking with Beer, which will help you pair your menu with appropriate beers.
What about all those beer vocabulary words that need a little explanation? For the Love of Hops by Stan Hieronymus, Malt: A Practical Guide from Field to Brewhouse by John Mallett and Yeast: The Practical Guide to Fermentation by Chris White will set you straight.