For the Love of Hops: The Practical Guide to Aroma, Bitterness and the Culture of Hops. By. Stan Hieronymus
Water: A Comprehensive Guide for Brewers. By. John Palmer and Colin Kaminski
Malt: A Practical Guide from Field to Brewhouse. By. John Mallett
Yeast: The Practical Guide to Beer Fermentation. By. Chris White and Jamil Zainasheff