The Encyclopedia of Diplomacy is an excellent reference work that covers the historical as well as the conceptual foundations of modern diplomacy and international relations. This four-volume set includes more than 400 entries written by scholars from around the world. Entries include prominent diplomatists (Powell, Colin), general concepts (Detente), techniques (Appeasement), theorists (Morgenthau, Hans J.) treaties (Treat of Antwerp), and conflicts (Austro-Prussian War). All entries are alphabetized, but the first volume begins with ahelpful lexicon showing all entries classified by the aforemenioned type. All contributors are identified, and biographical information is include. All entries ready very well, striking the right balance between authoritativeness and accessibility to the intended audience, and are cross-referenced. Reference sources and suggested further readings are a welcome feature for each entry. Overall, an excellent addition to the litearture. A reference work such as this one is likely to be used as an e-book, however. Summing Up: highly recommended. Lower-division undergraduates through faculty. --J.A. Knapp, Penn State University, CHOICEconnect October 2018 Vol. 56 No. 2